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Zhang ZP, Song SX, Liu YC, Zhu XR, Jiang YF, Shi LT, Jiang JZ, Miao MM. Mixed Transcriptome Analysis Revealed the Possible Interaction Mechanisms between Zizania latifolia and Ustilago esculenta Inducing Jiaobai Stem-Gall Formation. Int J Mol Sci 2021; 22:ijms222212258. [PMID: 34830140 PMCID: PMC8618054 DOI: 10.3390/ijms222212258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/06/2021] [Accepted: 11/09/2021] [Indexed: 11/23/2022] Open
Abstract
The smut fungus Ustilago esculenta infects Zizania latifolia and induces stem expansion to form a unique vegetable named Jiaobai. Although previous studies have demonstrated that hormonal control is essential for triggering stem swelling, the role of hormones synthesized by Z. latifolia and U. esculenta and the underlying molecular mechanism are not yet clear. To study the mechanism that triggers swollen stem formation, we analyzed the gene expression pattern of both interacting organisms during the initial trigger of culm gall formation, at which time the infective hyphae also propagated extensively and penetrated host stem cells. Transcriptional analysis indicated that abundant genes involving fungal pathogenicity and plant resistance were reprogrammed to maintain the subtle balance between the parasite and host. In addition, the expression of genes involved in auxin biosynthesis of U. esculenta obviously decreased during stem swelling, while a large number of genes related to the synthesis, metabolism and signal transduction of hormones of the host plant were stimulated and showed specific expression patterns, particularly, the expression of ZlYUCCA9 (a flavin monooxygenase, the key enzyme in indole-3-acetic acid (IAA) biosynthesis pathway) increased significantly. Simultaneously, the content of IAA increased significantly, while the contents of cytokinin and gibberellin showed the opposite trend. We speculated that auxin produced by the host plant, rather than the fungus, triggers stem swelling. Furthermore, from the differently expressed genes, two candidate Cys2-His2 (C2H2) zinc finger proteins, GME3058_g and GME5963_g, were identified from U. esculenta, which may conduct fungus growth and infection at the initial stage of stem-gall formation.
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Affiliation(s)
- Zhi-Ping Zhang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China; (Z.-P.Z.); (S.-X.S.); (Y.-C.L.); (X.-R.Z.); (Y.-F.J.); (L.-T.S.); (J.-Z.J.)
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College, Yangzhou University, Yangzhou 225009, China
| | - Si-Xiao Song
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China; (Z.-P.Z.); (S.-X.S.); (Y.-C.L.); (X.-R.Z.); (Y.-F.J.); (L.-T.S.); (J.-Z.J.)
| | - Yan-Cheng Liu
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China; (Z.-P.Z.); (S.-X.S.); (Y.-C.L.); (X.-R.Z.); (Y.-F.J.); (L.-T.S.); (J.-Z.J.)
| | - Xin-Rui Zhu
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China; (Z.-P.Z.); (S.-X.S.); (Y.-C.L.); (X.-R.Z.); (Y.-F.J.); (L.-T.S.); (J.-Z.J.)
| | - Yi-Feng Jiang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China; (Z.-P.Z.); (S.-X.S.); (Y.-C.L.); (X.-R.Z.); (Y.-F.J.); (L.-T.S.); (J.-Z.J.)
| | - Ling-Tong Shi
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China; (Z.-P.Z.); (S.-X.S.); (Y.-C.L.); (X.-R.Z.); (Y.-F.J.); (L.-T.S.); (J.-Z.J.)
| | - Jie-Zeng Jiang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China; (Z.-P.Z.); (S.-X.S.); (Y.-C.L.); (X.-R.Z.); (Y.-F.J.); (L.-T.S.); (J.-Z.J.)
| | - Min-Min Miao
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China; (Z.-P.Z.); (S.-X.S.); (Y.-C.L.); (X.-R.Z.); (Y.-F.J.); (L.-T.S.); (J.-Z.J.)
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College, Yangzhou University, Yangzhou 225009, China
- Correspondence:
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Ferreira-Gomes M, Wich M, Böde S, Hube B, Jacobsen ID, Jungnickel B. B Cell Recognition of Candida albicans Hyphae via TLR 2 Promotes IgG1 and IL-6 Secretion for T H17 Differentiation. Front Immunol 2021; 12:698849. [PMID: 34819929 PMCID: PMC8606576 DOI: 10.3389/fimmu.2021.698849] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 10/19/2021] [Indexed: 01/05/2023] Open
Abstract
Candida albicans is usually a benign member of the human gut microbiota, but can become pathogenic under certain circumstances, for example in an immunocompromised host. The innate immune system, in particular neutrophils and macrophages, constitutes a crucial first line of defense against fungal invasion, however adaptive immunity may provide long term protection and thus allow vaccination of at risk patients. While TH1 and TH17 cells are important for antifungal responses, the role of B cells and antibodies in protection from C. albicans infection is less well defined. In this study, we show that C. albicans hyphae but not yeast, as well as fungal cell wall components, directly activate B cells via MyD88 signaling triggered by Toll- like receptor 2, leading to increased IgG1 production. While Dectin-1 signals and specific recognition by the B cell receptor are dispensable for B cell activation in this system, TLR2/MyD88 signals cooperate with CD40 signals in promoting B cell activation. Importantly, recognition of C. albicans via MyD88 signaling is also essential for induction of IL-6 secretion by B cells, which promotes TH17 polarization in T-B cell coculture experiments. B cells may thus be activated directly by C. albicans in its invasive form, leading to production of antibodies and T cell help for fungal clearance.
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Affiliation(s)
- Marta Ferreira-Gomes
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Melissa Wich
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Sally Böde
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Bernhard Hube
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Ilse D. Jacobsen
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany
| | - Berit Jungnickel
- Institute of Biochemistry and Biophysics, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
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3
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MacAlpine J, Daniel-Ivad M, Liu Z, Yano J, Revie NM, Todd RT, Stogios PJ, Sanchez H, O'Meara TR, Tompkins TA, Savchenko A, Selmecki A, Veri AO, Andes DR, Fidel PL, Robbins N, Nodwell J, Whitesell L, Cowen LE. A small molecule produced by Lactobacillus species blocks Candida albicans filamentation by inhibiting a DYRK1-family kinase. Nat Commun 2021; 12:6151. [PMID: 34686660 PMCID: PMC8536679 DOI: 10.1038/s41467-021-26390-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/01/2021] [Indexed: 11/23/2022] Open
Abstract
The fungus Candida albicans is an opportunistic pathogen that can exploit imbalances in microbiome composition to invade its human host, causing pathologies ranging from vaginal candidiasis to fungal sepsis. Bacteria of the genus Lactobacillus are colonizers of human mucosa and can produce compounds with bioactivity against C. albicans. Here, we show that some Lactobacillus species produce a small molecule under laboratory conditions that blocks the C. albicans yeast-to-filament transition, an important virulence trait. It remains unexplored whether the compound is produced in the context of the human host. Bioassay-guided fractionation of Lactobacillus-conditioned medium linked this activity to 1-acetyl-β-carboline (1-ABC). We use genetic approaches to show that filamentation inhibition by 1-ABC requires Yak1, a DYRK1-family kinase. Additional biochemical characterization of structurally related 1-ethoxycarbonyl-β-carboline confirms that it inhibits Yak1 and blocks C. albicans biofilm formation. Thus, our findings reveal Lactobacillus-produced 1-ABC can prevent the yeast-to-filament transition in C. albicans through inhibition of Yak1.
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Affiliation(s)
- Jessie MacAlpine
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | | | - Zhongle Liu
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Junko Yano
- Center of Excellence in Oral and Craniofacial Biology, Louisiana State University Health Sciences Center School of Dentistry, New Orleans, LA, USA
| | - Nicole M Revie
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Robert T Todd
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Peter J Stogios
- BioZone, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Center for Structural Genomics of Infectious Diseases (CSGID), Chicago, IL, USA
| | - Hiram Sanchez
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Teresa R O'Meara
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Thomas A Tompkins
- Rosell Institute for Microbiome and Probiotics, 6100 Avenue Royalmount, Montreal, QC, Canada
| | - Alexei Savchenko
- BioZone, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Center for Structural Genomics of Infectious Diseases (CSGID), Chicago, IL, USA
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
| | - Anna Selmecki
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Amanda O Veri
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - David R Andes
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Paul L Fidel
- Center of Excellence in Oral and Craniofacial Biology, Louisiana State University Health Sciences Center School of Dentistry, New Orleans, LA, USA
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Justin Nodwell
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
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Tan CT, Xu X, Qiao Y, Wang Y. A peptidoglycan storm caused by β-lactam antibiotic's action on host microbiota drives Candida albicans infection. Nat Commun 2021; 12:2560. [PMID: 33963193 PMCID: PMC8105390 DOI: 10.1038/s41467-021-22845-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 04/01/2021] [Indexed: 02/07/2023] Open
Abstract
The commensal fungus Candida albicans often causes life-threatening infections in patients who are immunocompromised with high mortality. A prominent but poorly understood risk factor for the C. albicans commensal‒pathogen transition is the use of broad-spectrum antibiotics. Here, we report that β-lactam antibiotics cause bacteria to release significant quantities of peptidoglycan fragments that potently induce the invasive hyphal growth of C. albicans. We identify several active peptidoglycan subunits, including tracheal cytotoxin, a molecule produced by many Gram-negative bacteria, and fragments purified from the cell wall of Gram-positive Staphylococcus aureus. Feeding mice with β-lactam antibiotics causes a peptidoglycan storm that transforms the gut from a niche usually restraining C. albicans in the commensal state to promoting invasive growth, leading to systemic dissemination. Our findings reveal a mechanism underlying a significant risk factor for C. albicans infection, which could inform clinicians regarding future antibiotic selection to minimize this deadly disease incidence.
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Affiliation(s)
- Chew Teng Tan
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Xiaoli Xu
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore
| | - Yuan Qiao
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore.
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
| | - Yue Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore.
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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Bain JM, Alonso MF, Childers DS, Walls CA, Mackenzie K, Pradhan A, Lewis LE, Louw J, Avelar GM, Larcombe DE, Netea MG, Gow NAR, Brown GD, Erwig LP, Brown AJP. Immune cells fold and damage fungal hyphae. Proc Natl Acad Sci U S A 2021; 118:e2020484118. [PMID: 33876755 PMCID: PMC8053999 DOI: 10.1073/pnas.2020484118] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Innate immunity provides essential protection against life-threatening fungal infections. However, the outcomes of individual skirmishes between immune cells and fungal pathogens are not a foregone conclusion because some pathogens have evolved mechanisms to evade phagocytic recognition, engulfment, and killing. For example, Candida albicans can escape phagocytosis by activating cellular morphogenesis to form lengthy hyphae that are challenging to engulf. Through live imaging of C. albicans-macrophage interactions, we discovered that macrophages can counteract this by folding fungal hyphae. The folding of fungal hyphae is promoted by Dectin-1, β2-integrin, VASP, actin-myosin polymerization, and cell motility. Folding facilitates the complete engulfment of long hyphae in some cases and it inhibits hyphal growth, presumably tipping the balance toward successful fungal clearance.
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Affiliation(s)
- Judith M Bain
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
| | - M Fernanda Alonso
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
| | - Delma S Childers
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
| | - Catriona A Walls
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
| | - Kevin Mackenzie
- Microscopy and Histology Facility, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
| | - Arnab Pradhan
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, University of Exeter, EX4 4QD Exeter, United Kingdom
| | - Leanne E Lewis
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
| | - Johanna Louw
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
| | - Gabriela M Avelar
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
| | - Daniel E Larcombe
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, University of Exeter, EX4 4QD Exeter, United Kingdom
| | - Mihai G Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, 6500HB Nijmegen, The Netherlands
- Department for Immunology and Metabolism, Life and Medical Sciences Institute, University of Bonn, 53115 Bonn, Germany
| | - Neil A R Gow
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, University of Exeter, EX4 4QD Exeter, United Kingdom
| | - Gordon D Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
- Medical Research Council Centre for Medical Mycology, University of Exeter, EX4 4QD Exeter, United Kingdom
| | - Lars P Erwig
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom
- Johnson-Johnson Innovation, Europe, Middle East and Africa Innovation Centre, London W1G 0BG, United Kingdom
| | - Alistair J P Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, AB25 2ZD Aberdeen, United Kingdom;
- Medical Research Council Centre for Medical Mycology, University of Exeter, EX4 4QD Exeter, United Kingdom
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Ueda K, Nakajima Y, Inoue H, Kobayashi K, Nishiuchi T, Kimura M, Yaeno T. Nicotinamide Mononucleotide Potentiates Resistance to Biotrophic Invasion of Fungal Pathogens in Barley. Int J Mol Sci 2021; 22:ijms22052696. [PMID: 33800043 PMCID: PMC7962114 DOI: 10.3390/ijms22052696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/19/2021] [Accepted: 02/26/2021] [Indexed: 11/16/2022] Open
Abstract
Nicotinamide mononucleotide (NMN), a precursor of nicotinamide adenine dinucleotide (NAD), induces disease resistance to the Fusarium head blight fungus Fusarium graminearum in Arabidopsis and barley, but it is unknown at which stage of the infection it acts. Since the rate of haustorial formation of an obligate biotrophic barley powdery mildew fungus Blumeria graminis f. sp. hordei (Bgh) was significantly reduced in NMN-treated coleoptile epidermal cells, the possibility that NMN induces resistance to the biotrophic stage of F. graminearum was investigated. The results show that NMN treatment caused the wandering of hyphal growth and suppressed the formation of appressoria-like structures. Furthermore, we developed an experimental system to monitor the early stage of infection in real-time and analyzed the infection behavior. We observed that the hyphae elongated windingly by NMN treatment. These results suggest that NMN potentiates resistance to the biotrophic invasion of F. graminearum as well as Bgh.
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Affiliation(s)
- Kana Ueda
- Department of Agriculture, Ehime University, Tarumi, Matsuyama, Ehime 790-8566, Japan; (K.U.); (H.I.); (K.K.)
| | - Yuichi Nakajima
- Division of Molecular and Cellular Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8601, Japan; (Y.N.); (M.K.)
| | - Hiroshi Inoue
- Department of Agriculture, Ehime University, Tarumi, Matsuyama, Ehime 790-8566, Japan; (K.U.); (H.I.); (K.K.)
| | - Kappei Kobayashi
- Department of Agriculture, Ehime University, Tarumi, Matsuyama, Ehime 790-8566, Japan; (K.U.); (H.I.); (K.K.)
| | - Takumi Nishiuchi
- Institution for Gene Research, Advanced Science Research Centre, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-0934, Japan;
| | - Makoto Kimura
- Division of Molecular and Cellular Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8601, Japan; (Y.N.); (M.K.)
| | - Takashi Yaeno
- Department of Agriculture, Ehime University, Tarumi, Matsuyama, Ehime 790-8566, Japan; (K.U.); (H.I.); (K.K.)
- Correspondence:
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Xu T, Qin D, Muhae Ud Din G, Liu T, Chen W, Gao L. Characterization of histological changes at the tillering stage (Z21) in resistant and susceptible wheat plants infected by Tilletia controversa Kühn. BMC Plant Biol 2021; 21:49. [PMID: 33461490 PMCID: PMC7814547 DOI: 10.1186/s12870-020-02819-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 12/25/2020] [Indexed: 05/03/2023]
Abstract
BACKGROUND Dwarf bunt, which is caused by Tilletia controversa Kühn, is a soilborne and seedborne disease that occurs worldwide and can lead to 70% or even total losses of wheat crops. However, very little information is available about the histological changes that occur in dwarf bunt-resistant and dwarf bunt-susceptible wheat plants at the tillering stage (Z21). In this study, we used scanning electron microscopy and transmission electron microscopy to characterize the histological changes at this stage in resistant and susceptible wheat cultivars infected by T. controversa. RESULTS Using scanning electron microscopy, the root, stem, and leaf structures of resistant and susceptible cultivars were examined after T. controversa infection. The root epidermal and vascular bundles were more severely damaged in the susceptible T. controversa-infected plants than in the resistant plants. The stem cell and longitudinal sections were much more extensively affected in susceptible plants than in resistant plants after pathogen infection. However, slightly deformed mesophyll cells were observed in the leaves of susceptible plants. With transmission electron microscopy, we found that the cortical bundle cells and the cell contents and nuclei in the roots were more severely affected in the susceptible plants than in the resistant plants; in the stems and leaves, the nuclei, chloroplasts, and mesophyll cells changed significantly in the susceptible plants after fungal infection. Moreover, we found that infected susceptible and resistant plants were affected much more severely at the tillering stage (Z21) than at the seedling growth stage (Z13). CONCLUSION Histological changes in the wheat roots, stems and leaves were much more severe in T. controversa-infected susceptible plants than in infected resistant plants at the tillering stage (Z21).
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Affiliation(s)
- Tongshuo Xu
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Dandan Qin
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Ghulam Muhae Ud Din
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Taiguo Liu
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Wanquan Chen
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Li Gao
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
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Abd El-Baky RM, Mandour SA, Ahmed EF, Hashem ZS, Sandle T, Mohamed DS. Virulence profiles of some Pseudomonas aeruginosa clinical isolates and their association with the suppression of Candida growth in polymicrobial infections. PLoS One 2020; 15:e0243418. [PMID: 33290412 PMCID: PMC7723275 DOI: 10.1371/journal.pone.0243418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 11/22/2020] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that can cause a variety of diseases especially in the hospital environment. However, this pathogen also exhibits antimicrobial activity against Gram-positive bacteria and fungi. This study aimed to characterize different virulence factors, secreted metabolites and to study their role in the suppression of Candida growth. Fifteen P. aeruginosa isolates were tested for their anticandidal activity against 3 different Candida spp. by the cross-streak method. The effect on hyphae production was tested microscopically using light and scanning electron microscopy (SEM). Polymerase chain reaction was used in the detection of some virulence genes. Lipopolysaccharide profile was performed using SDS-polyacrylamide gel stained with silver. Fatty acids were analyzed by GC-MS as methyl ester derivatives. It was found that 5 P. aeruginosa isolates inhibited all tested Candida spp. (50-100% inhibition), one isolate inhibited C. glabrata only and 3 isolates showed no activity against the tested Candida spp. The P. aeruginosa isolates inhibiting all Candida spp. were positive for all virulence genes. GC-Ms analysis revealed that isolates with high anticandidal activity showed spectra for several compounds, each known for their antifungal activity in comparison to those with low or no anticandidal activity. Hence, clinical isolates of P. aeruginosa showed Candida species-specific interactions by different means, giving rise to the importance of studying microbial interaction in polymicrobial infections and their contribution to causing disease.
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Affiliation(s)
- Rehab Mahmoud Abd El-Baky
- Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia, Egypt
- Department of Microbiology and Immunology, Faculty of Pharmacy, Deraya University, Minia, Egypt
| | - Sahar A. Mandour
- Department of Microbiology and Immunology, Faculty of Pharmacy, Deraya University, Minia, Egypt
| | - Eman Farouk Ahmed
- Department of Microbiology and Immunology, Faculty of Pharmacy, Deraya University, Minia, Egypt
| | - Zeinab Shawky Hashem
- Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia, Egypt
| | - Tim Sandle
- School of Health Sciences, Division of Pharmacy & Optometry, University of Manchester, Manchester, United Kingdom
| | - Doaa Safwat Mohamed
- Department of Microbiology and Immunology, Faculty of Pharmacy, Deraya University, Minia, Egypt
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Igbalajobi O, Gao J, Fischer R. The HOG Pathway Plays Different Roles in Conidia and Hyphae During Virulence of Alternaria alternata. Mol Plant Microbe Interact 2020; 33:1405-1410. [PMID: 33104446 DOI: 10.1094/mpmi-06-20-0165-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The black mold Alternaria alternata causes dramatic losses in agriculture due to postharvest colonization and mycotoxin formation and is a weak pathogen on living plants. Fungal signaling processes are crucial for successful colonization of a host plant. Because the mitogen-activated protein kinase HogA is important for the expression of stress-associated genes, we tested a ∆hogA-deletion strain for pathogenicity. When conidia were used as inoculum, the ∆hogA-deletion strain was largely impaired in colonizing tomato and apple. In comparison, hyphae as inoculum colonized the fruit very well. Hence, HogA appears to be important only in the initial stages of plant colonization. A similar difference between conidial inoculum and hyphal inoculum was observed on artificial medium in the presence of different stress agents. Whereas wild-type conidia adapted well to different stresses, the ∆hogA-deletion strain failed to grow under the same conditions. With hyphae as inoculum, the wild type and the ∆hogA-deletion strain grew in a very similar way. At the molecular level, we observed upregulation of several catalase (catA, -B, and -D) and superoxide dismutase (sodA, -B, and -E) genes in germlings but not in hyphae after exposure to 4 mM hydrogen peroxide. The upregulation required the high osmolarity glycerol (HOG) pathway. In contrast, in mycelia, catD, sodA, sodB, and sodE were upregulated upon stress in the absence of HogA. Several other stress-related genes behaved in a similar way.
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Affiliation(s)
- Olumuyiwa Igbalajobi
- Karlsruhe Institute of Technology (KIT)-South Campus, Institute of Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4,D-76131 Karlsruhe, Germany
| | - Jia Gao
- Karlsruhe Institute of Technology (KIT)-South Campus, Institute of Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4,D-76131 Karlsruhe, Germany
| | - Reinhard Fischer
- Karlsruhe Institute of Technology (KIT)-South Campus, Institute of Applied Biosciences, Department of Microbiology, Fritz-Haber-Weg 4,D-76131 Karlsruhe, Germany
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Zhao X, Tang B, Xu J, Wang N, Zhou Z, Zhang J. A SET domain-containing protein involved in cell wall integrity signaling and peroxisome biogenesis is essential for appressorium formation and pathogenicity of Colletotrichum gloeosporioides. Fungal Genet Biol 2020; 145:103474. [PMID: 33007450 DOI: 10.1016/j.fgb.2020.103474] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 08/18/2020] [Accepted: 09/24/2020] [Indexed: 11/19/2022]
Abstract
The chromatin modulator Set5 plays important regulatory roles in both cell growth and stress responses of Saccharomyces cerevisiae. However, its function in filamentous fungi remains poorly understood. Here, we report the pathogenicity-related gene CgSET5 discovered in a T-DNA insertional mutant M285 of Colletotrichum gloeosporioides. Bioinformatic analysis revealed that CgSET5 encodes a SET domain-containing protein that is a homolog of the budding yeast S. cerevisiae Set5. CgSET5 is important for hyphae growth and conidiation and is necessary for appressorium formation and pathogenicity. CgSet5 regulates appressorium formation in a mitogen-activated protein kinase-independent manner. Inactivation of CgSET5 resulted in a significant reduction in chitin content within the cell wall, indicating CgSet5 plays a vital role in cell wall integrity. CgSet5 is involved in peroxisome biogenesis. We identified CgSet5 as the histone H4 methyltransferase, which methylates the critical H4 lysine residues 5 and 8 in C. gloeosporioides. We carried out a yeast two-hybrid screen to find CgSet5 interacting partners. We found CgSet5 putatively interacts with an inorganic pyrophosphatase named CgPpa1, which co-localized in the cytoplasm with CgSet5. Finally, CgPpa1 was found to strongly interact with CgSet5 in vivo during appressorium formation by bimolecular fluorescence complementation assays. These data corroborate a complex control function of CgSet5 acting as a core pathogenic regulator, which connects cell wall integrity and peroxisome biogenesis in C. gloeosporioides.
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Affiliation(s)
- Xuanzhu Zhao
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Germplasm Resources Utilization), Ministry of Agriculture, Xingcheng 125100, China
| | - Bozeng Tang
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park NR4 7UH, UK
| | - Jie Xu
- Research Institute of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng 125100, China
| | - Na Wang
- Research Institute of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng 125100, China
| | - Zongshan Zhou
- Research Institute of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng 125100, China
| | - Junxiang Zhang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Germplasm Resources Utilization), Ministry of Agriculture, Xingcheng 125100, China.
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Liu Y, Liu J, Li G, Zhang M, Zhang Y, Wang Y, Hou J, Yang S, Sun J, Qin Q. A novel Botrytis cinerea-specific gene BcHBF1 enhances virulence of the grey mould fungus via promoting host penetration and invasive hyphal development. Mol Plant Pathol 2019; 20:731-747. [PMID: 31008573 PMCID: PMC6637910 DOI: 10.1111/mpp.12788] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Botrytis cinerea is the causative agent of grey mould on over 1000 plant species and annually causes enormous economic losses worldwide. However, the fungal factors that mediate pathogenesis of the pathogen remain largely unknown. Here, we demonstrate that a novel B. cinerea-specific pathogenicity-associated factor BcHBF1 (hyphal branching-related factor 1), identified from virulence-attenuated mutant M8008 from a B. cinerea T-DNA insertion mutant library, plays an important role in hyphal branching, infection structure formation, sclerotial formation and full virulence of the pathogen. Deletion of BcHBF1 in B. cinerea did not impair radial growth of mycelia, conidiation, conidial germination, osmotic- and oxidative-stress adaptation, as well as cell wall integrity of the ∆Bchbf1 mutant strains. However, loss of BcHBF1 impaired the capability of hyphal branching, appressorium and infection cushion formation, appressorium host penetration and virulence of the pathogen. Moreover, disruption of BcHBF1 altered conidial morphology and dramatically impaired sclerotial formation of the mutant strains. Complementation of BcHBF1 completely rescued all the phenotypic defects of the ∆Bchbf1 mutants. During young hyphal branching, host penetration and early invasive growth of the pathogen, BcHBF1 expression was up-regulated, suggesting that BcHBF1 is required for these processes. Our findings provide novel insights into the fungal factor mediating pathogenesis of the grey mould fungus via regulation of its infection structure formation, host penetration and invasive hyphal branching and growth.
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Affiliation(s)
- Yue Liu
- College of Plant SciencesKey Laboratory of Zoonosis Research, Ministry of Education, Jilin UniversityChangchun130062China
| | - Jiane‐Kang Liu
- College of Plant SciencesKey Laboratory of Zoonosis Research, Ministry of Education, Jilin UniversityChangchun130062China
- Present address:
College of Life SciencesTsinghua UniversityBeijing100084China
| | - Gui‐Hua Li
- College of Plant SciencesJilin UniversityChangchun130062China
| | - Ming‐Zhe Zhang
- College of Plant SciencesJilin UniversityChangchun130062China
| | - Ying‐Ying Zhang
- College of Plant SciencesJilin UniversityChangchun130062China
| | - Yuan‐Yuan Wang
- College of Plant SciencesJilin UniversityChangchun130062China
| | - Jie Hou
- College of Plant SciencesJilin UniversityChangchun130062China
- Department of ForestForest College of Beihua UniversityJilin132013China
| | - Song Yang
- College of Plant SciencesJilin UniversityChangchun130062China
| | - Jiao Sun
- College of Plant SciencesJilin UniversityChangchun130062China
| | - Qing‐Ming Qin
- College of Plant SciencesKey Laboratory of Zoonosis Research, Ministry of Education, Jilin UniversityChangchun130062China
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12
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Guo Y, Yao S, Yuan T, Wang Y, Zhang D, Tang W. The spatiotemporal control of KatG2 catalase-peroxidase contributes to the invasiveness of Fusarium graminearum in host plants. Mol Plant Pathol 2019; 20:685-700. [PMID: 30919582 PMCID: PMC6637876 DOI: 10.1111/mpp.12785] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Reactive oxygen species (ROS) are involved in the pathogen-host interactions, and play a Janus-faced role in the resistance and susceptibility of plants to biotrophic and necrotrophic pathogens. The ascomycete fungus Fusarium graminearum causes hazardous wheat Fusarium head blight worldwide. Deletion of the putative secreted catalase-peroxidase gene in F. graminearum, KatG2, reduced the virulence in wheat spike infection. However, it remains unclear when and where KatG2 scavenges ROS during the invasion of wheat. In this study, we delineate the change in ROS levels in the transition of the infection phase under microscopic observation. Correspondingly, the pathogen switches its strategy of infection with temporal and spatial regulation of KatG2 to counteract oxidative stress generated by host plant cells. With the native promoter-driven KatG2-mRFP strain, we show that KatG2-mRFP expression was induced in planta and accumulated in the infection front region at the early infection stage. In contrast to its ubiquitous cellular localization in runner hyphae, KatG2-mRFP is exclusively located on the cell wall of invading hyphal cells, especially at the pathogen-host cellular interface. Using posttranslational modification analysis, we found that asparagine residues at the 238 and 391 positions of KatG2 could be modified by N-glycosylation and that these two residues are required for KatG2 accumulation and cell wall localization in planta.
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Affiliation(s)
- Yan Guo
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghai200032China
- University of the Chinese Academy of SciencesChina
| | - Shenghua Yao
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghai200032China
- School of Life ScienceEast China Normal UniversityShanghai200062China
- Shanghai High School International DivisionShanghai200231China
| | - Tinglu Yuan
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghai200032China
| | - Yanzhang Wang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghai200032China
| | - Dong Zhang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghai200032China
| | - Weihua Tang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghai200032China
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Douglas LM, Konopka JB. Plasma membrane architecture protects Candida albicans from killing by copper. PLoS Genet 2019; 15:e1007911. [PMID: 30633741 PMCID: PMC6345494 DOI: 10.1371/journal.pgen.1007911] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 01/24/2019] [Accepted: 12/20/2018] [Indexed: 12/21/2022] Open
Abstract
The ability to resist copper toxicity is important for microbial pathogens to survive attack by innate immune cells. A sur7Δ mutant of the fungal pathogen Candida albicans exhibits decreased virulence that correlates with increased sensitivity to copper, as well as defects in other stress responses and morphogenesis. Previous studies indicated that copper kills sur7Δ cells by a mechanism distinct from the known resistance pathways involving the Crp1 copper exporter or the Cup1 metallothionein. Since Sur7 resides in punctate plasma membrane domains known as MCC/eisosomes, we examined overexpression of SUR7 and found that it rescued the copper sensitivity of a mutant that fails to form MCC/eisosomes (pil1Δ lsp1Δ), indicating that these domains act to facilitate Sur7 function. Genetic screening identified new copper-sensitive mutants, the strongest of which were similar to sur7Δ in having altered plasma membranes due to defects in membrane trafficking, cortical actin, and morphogenesis (rvs161Δ, rvs167Δ, and arp2Δ arp3Δ). Consistent with the mutants having altered plasma membrane organization, they were all more readily permeabilized by copper, which is known to bind phosphatidylserine and phosphatidylethanolamine and cause membrane damage. Although these phospholipids are normally localized to the intracellular leaflet of the plasma membrane, their exposure on the surface of the copper-sensitive mutants was indicated by increased susceptibility to membrane damaging agents that bind to these phospholipids. Increased copper sensitivity was also detected for a drs2Δ mutant, which lacks a phospholipid flippase that is involved in maintaining phospholipid asymmetry. Copper binds phosphatidylserine with very high affinity, and deleting CHO1 to prevent phosphatidylserine synthesis rescued the copper sensitivity of sur7Δ cells, confirming a major role for phosphatidylserine in copper sensitivity. These results highlight how proper plasma membrane architecture protects fungal pathogens from copper and attack by the immune system, thereby opening up new avenues for therapeutic intervention. The transition metal copper is used by the innate immune system to attack microbial pathogens. To better understand how the human fungal pathogen Candida albicans resists this type of stress, we screened for mutants that were more susceptible to killing by copper. Interestingly, we identified a new class of copper-sensitive mutants whose plasma membranes are more readily permeabilized by copper. The common characteristic of these new copper-sensitive mutants is that they have an altered cell surface, which weakened their resistance to copper. These results help to explain the toxic effects of copper and suggest novel therapeutic strategies for fungal infections.
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Affiliation(s)
- Lois M. Douglas
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - James B. Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
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14
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Polvi EJ, Veri AO, Liu Z, Hossain S, Hyde S, Kim SH, Tebbji F, Sellam A, Todd RT, Xie JL, Lin ZY, Wong CJ, Shapiro RS, Whiteway M, Robbins N, Gingras AC, Selmecki A, Cowen LE. Functional divergence of a global regulatory complex governing fungal filamentation. PLoS Genet 2019; 15:e1007901. [PMID: 30615616 PMCID: PMC6336345 DOI: 10.1371/journal.pgen.1007901] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 01/17/2019] [Accepted: 12/16/2018] [Indexed: 01/17/2023] Open
Abstract
Morphogenetic transitions are prevalent in the fungal kingdom. For a leading human fungal pathogen, Candida albicans, the capacity to transition between yeast and filaments is key for virulence. For the model yeast Saccharomyces cerevisiae, filamentation enables nutrient acquisition. A recent functional genomic screen in S. cerevisiae identified Mfg1 as a regulator of morphogenesis that acts in complex with Flo8 and Mss11 to mediate transcriptional responses crucial for filamentation. In C. albicans, Mfg1 also interacts physically with Flo8 and Mss11 and is critical for filamentation in response to diverse cues, but the mechanisms through which it regulates morphogenesis remained elusive. Here, we explored the consequences of perturbation of Mfg1, Flo8, and Mss11 on C. albicans morphogenesis, and identified functional divergence of complex members. We observed that C. albicans Mss11 was dispensable for filamentation, and that overexpression of FLO8 caused constitutive filamentation even in the absence of Mfg1. Harnessing transcriptional profiling and chromatin immunoprecipitation coupled to microarray analysis, we identified divergence between transcriptional targets of Flo8 and Mfg1 in C. albicans. We also established that Flo8 and Mfg1 cooperatively bind to promoters of key regulators of filamentation, including TEC1, for which overexpression was sufficient to restore filamentation in the absence of Flo8 or Mfg1. To further explore the circuitry through which Mfg1 regulates morphogenesis, we employed a novel strategy to select for mutations that restore filamentation in the absence of Mfg1. Whole genome sequencing of filamentation-competent mutants revealed chromosome 6 amplification as a conserved adaptive mechanism. A key determinant of the chromosome 6 amplification is FLO8, as deletion of one allele blocked morphogenesis, and chromosome 6 was not amplified in evolved lineages for which FLO8 was re-located to a different chromosome. Thus, this work highlights rewiring of key morphogenetic regulators over evolutionary time and aneuploidy as an adaptive mechanism driving fungal morphogenesis. Fungal infections pose a severe burden to human health worldwide. Candida albicans is a leading cause of systemic fungal infections, with mortality rates approaching 40%. One of the key virulence traits of this fungus is its ability to transition between yeast and filamentous forms in response to diverse host-relevant cues. The model yeast Saccharomyces cerevisiae is also capable of filamentous growth in certain conditions, and previous work has identified a key transcriptional complex required for filamentation in both species. However, here we discover that the circuitry governed by this complex in C. albicans is largely distinct from that in the non-pathogenic S. cerevisiae. We also employ a novel selection strategy to perform experimental evolution, identifying chromosome triplication as a mechanism to restore filamentation in a non-filamentous mutant. This work reveals unique circuitry governing a key virulence trait in a leading fungal pathogen, identifying potential therapeutic targets to combat these life-threatening infections.
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Affiliation(s)
- Elizabeth J. Polvi
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Amanda O. Veri
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Zhongle Liu
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Saif Hossain
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Sabrina Hyde
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Sang Hu Kim
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Faiza Tebbji
- Infectious Disease Research Centre, Université Laval, Quebec, Canada
| | - Adnane Sellam
- Infectious Disease Research Centre, Université Laval, Quebec, Canada
| | - Robert T. Todd
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Jinglin L. Xie
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Ontario, Canada
| | - Cassandra J. Wong
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Ontario, Canada
| | - Rebecca S. Shapiro
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | | | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Ontario, Canada
| | - Anna Selmecki
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
- * E-mail:
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Sun G, Elowsky C, Li G, Wilson RA. TOR-autophagy branch signaling via Imp1 dictates plant-microbe biotrophic interface longevity. PLoS Genet 2018; 14:e1007814. [PMID: 30462633 PMCID: PMC6281275 DOI: 10.1371/journal.pgen.1007814] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 12/05/2018] [Accepted: 11/06/2018] [Indexed: 01/07/2023] Open
Abstract
Like other intracellular eukaryotic phytopathogens, the devastating rice blast fungus Magnaporthe (Pyricularia) oryzae first infects living host cells by elaborating invasive hyphae (IH) surrounded by a plant-derived membrane. This forms an extended biotrophic interface enclosing an apoplastic compartment into which fungal effectors can be deployed to evade host detection. M. oryzae also forms a focal, plant membrane-rich structure, the biotrophic interfacial complex (BIC), that accumulates cytoplasmic effectors for translocation into host cells. Molecular decision-making processes integrating fungal growth and metabolism in host cells with interface function and dynamics are unknown. Here, we report unanticipated roles for the M. oryzae Target-of-Rapamycin (TOR) nutrient-signaling pathway in mediating plant-fungal biotrophic interface membrane integrity. Through a forward genetics screen for M. oryzae mutant strains resistant to the specific TOR kinase inhibitor rapamycin, we discovered IMP1 encoding a novel vacuolar protein required for membrane trafficking, V-ATPase assembly, organelle acidification and autophagy induction. During infection, Δimp1 deletants developed intracellular IH in the first infected rice cell following cuticle penetration. However, fluorescently labeled effector probes revealed that interface membrane integrity became compromised as biotrophy progressed, abolishing the BIC and releasing apoplastic effectors into host cytoplasm. Growth between rice cells was restricted. TOR-independent autophagy activation in Δimp1 deletants (following infection) remediated interface function and cell-to-cell growth. Autophagy inhibition in wild type (following infection) recapitulated Δimp1. In addition to vacuoles, Imp1GFP localized to IH membranes in an autophagy-dependent manner. Collectively, our results suggest TOR-Imp1-autophagy branch signaling mediates membrane homeostasis to prevent catastrophic erosion of the biotrophic interface, thus facilitating fungal growth in living rice cells. The significance of this work lays in elaborating a novel molecular mechanism of infection stressing the dominance of fungal metabolism and metabolic control in sustaining long-term plant-microbe interactions. This work also has implications for understanding the enigmatic biotrophy to necrotrophy transition. Plant-associated fungi can form intimate connections with living host cells. Clarifying the molecular drivers of these interactions, and which partner is dominant, might be important in understanding how beneficial plant-fungal relationships can be enhanced to improve crop yields while pathogenic interactions that threaten crop health are disrupted. In common with other symbionts and phytopathogens, the devastating rice blast fungus Magnaporthe oryzae elaborates invasive hyphae in living host cells surrounded by plant-derived membranes. Nothing is known at the molecular signaling level about how such plant-microbe biotrophic interfacial zones are maintained as the fungus grows in and between host cells. Here, we report that fungal membrane trafficking processes controlled by nutrient signaling pathways are critical for maintaining biotrophic interface integrity during M. oryzae growth in rice cells. Impairing these processes resulted in erosion of the plant-microbe interface and failure of the fungus to thrive. To our knowledge, this work presents the first evidence indicating that the fungal partner is dominant in propagating the plant-microbe boundary. This suggests that the biotrophic interface is a fungal construct and provides clues on how such interfaces might be modulated to benefit the host plant.
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Affiliation(s)
- Guangchao Sun
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Christian Elowsky
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Gang Li
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Richard A. Wilson
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
- * E-mail:
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Manoharan RK, Lee J, Lee J. Efficacy of 7-benzyloxyindole and other halogenated indoles to inhibit Candida albicans biofilm and hyphal formation. Microb Biotechnol 2018; 11:1060-1069. [PMID: 29656577 PMCID: PMC6196399 DOI: 10.1111/1751-7915.13268] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 11/29/2022] Open
Abstract
Certain pathogenic bacteria and yeast form biofilms on biotic and abiotic surfaces including medical devices and implants. Hence, the development of antibiofilm coating materials becomes relevant. The virulence of those colonizing pathogens can be reduced by inhibiting biofilm formation rather than killing pathogens using excessive amounts of antimicrobials, which is touted as one of the main reasons for the development of drug resistance. Candida albicans is an opportunistic fungal pathogen, and the transition of yeast cells to hyphal cells is believed to be a crucial virulence factor. Previous studies have shown that indole and its derivatives possess antivirulence properties against various bacterial pathogens. In this study, we used various indole derivatives to investigate biofilm-inhibiting activity against C. albicans. Our study revealed that 7-benzyloxyindole, 4-fluoroindole and 5-iodoindole effectively inhibited biofilm formation compared to the antifungal agent fluconazole. Particularly, 7-benzyloxyindole at 0.02 mM (4.5 μg ml-1 ) significantly reduced C. albicans biofilm formation, but had no effect on planktonic cells, and this finding was confirmed by a 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay and three-dimensional confocal laser scanning microscopy. Scanning electron microscopy analyses revealed that 7-benzyloxyindole effectively inhibited hyphal formation, which explains biofilm inhibition. Transcriptomic analysis showed that 7-benzyloxyindole downregulated the expressions of several hypha/biofilm-related genes (ALS3, ECE1, HWP1 and RBT1). A C. albicans-infected Caenorhabditis elegans model system was used to confirm the antivirulence efficacy of 7-benzyloxyindole.
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Affiliation(s)
| | - Jin‐Hyung Lee
- School of Chemical EngineeringYeungnam UniversityGyeongsan38541Korea
| | - Jintae Lee
- School of Chemical EngineeringYeungnam UniversityGyeongsan38541Korea
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Ren W, Tao J, Shi D, Chen W, Chen C. Involvement of a dihydrodipicolinate synthase gene (FaDHDPS1) in fungal development, pathogenesis and stress responses in Fusarium asiaticum. BMC Microbiol 2018; 18:128. [PMID: 30290767 PMCID: PMC6173861 DOI: 10.1186/s12866-018-1268-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 09/27/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Dihydrodipicolinate synthase (DHDPS) is an allosteric enzyme, which catalyzes the first unique step of lysine biosynthesis in prokaryotes, higher plants and some fungi. To date, the biological roles of DHDPS in filamentous fungi are poorly understood. RESULTS In this study, on the basis of comparative genome resequencing, a DHDPS gene was found to be specific in Fusarium asiaticum, named FaDHDPS1, which showed high amino acid identity to that of entomopathogenic fungus. Subcellular localization of the FaDHDPS1-GFP fusion protein was mainly concentrated in the cytoplasm of conidia and dispersed in the cytoplasm during conidial germination. To reveal the biological functions, both deletion and complementation mutants of FaDHDPS1 were generated. The results showed that the FaDHDPS1 deletion mutant was defective in conidiation, virulence and DON biosynthesis. In addition, deletion of FaDHDPS1 resulted in tolerance to sodium pyruvate, lysine, low temperature and Congo red. CONCLUSION Results of this study indicate that FaDHDPS1 plays an important role in the regulation of vegetative differentiation, pathogenesis and adaption to multiple stresses in F. asiaticum.
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Affiliation(s)
- Weichao Ren
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
| | - Jiting Tao
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
| | - Dongya Shi
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
| | - Wenchan Chen
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
| | - Changjun Chen
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu China
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18
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Li J, Zhang X, Li L, Liu J, Zhang Y, Pan H. Proteomics Analysis of SsNsd1-Mediated Compound Appressoria Formation in Sclerotinia sclerotiorum. Int J Mol Sci 2018; 19:E2946. [PMID: 30262736 PMCID: PMC6213358 DOI: 10.3390/ijms19102946] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 09/21/2018] [Accepted: 09/24/2018] [Indexed: 12/25/2022] Open
Abstract
Sclerotinia sclerotiorum (Lib.) de Bary is a devastating necrotrophic fungal pathogen attacking a broad range of agricultural crops. In this study, although the transcript accumulation of SsNsd1, a GATA-type IVb transcription factor, was much lower during the vegetative hyphae stage, its mutants completely abolished the development of compound appressoria. To further elucidate how SsNsd1 influenced the appressorium formation, we conducted proteomics-based analysis of the wild-type and ΔSsNsd1 mutant by two-dimensional electrophoresis (2-DE). A total number of 43 differentially expressed proteins (≥3-fold change) were observed. Of them, 77% were downregulated, whereas 14% were upregulated. Four protein spots fully disappeared in the mutants. Further, we evaluated these protein sequences by mass spectrometry analysis of the peptide mass and obtained functionally annotated 40 proteins, among which only 17 proteins (38%) were identified to have known functions including energy production, metabolism, protein fate, stress response, cellular organization, and cell growth and division. However, the remaining 23 proteins (56%) were characterized as hypothetical proteins among which four proteins (17%) were predicted to contain the signal peptides. In conclusion, the differentially expressed proteins identified in this study shed light on the ΔSsNsd1 mutant-mediated appressorium deficiency and can be used in future investigations to better understand the signaling mechanisms of SsNsd1 in S. sclerotiorum.
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Affiliation(s)
- Jingtao Li
- College of Plant Science, Jilin University, Changchun 130062, China.
- College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, China.
| | - Xianghui Zhang
- College of Plant Science, Jilin University, Changchun 130062, China.
| | - Le Li
- College of Plant Science, Jilin University, Changchun 130062, China.
| | - Jinliang Liu
- College of Plant Science, Jilin University, Changchun 130062, China.
| | - Yanhua Zhang
- College of Plant Science, Jilin University, Changchun 130062, China.
| | - Hongyu Pan
- College of Plant Science, Jilin University, Changchun 130062, China.
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19
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Pericolini E, Perito S, Castagnoli A, Gabrielli E, Mencacci A, Blasi E, Vecchiarelli A, Wheeler RT. Epitope unmasking in vulvovaginal candidiasis is associated with hyphal growth and neutrophilic infiltration. PLoS One 2018; 13:e0201436. [PMID: 30063729 PMCID: PMC6067721 DOI: 10.1371/journal.pone.0201436] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 07/16/2018] [Indexed: 11/29/2022] Open
Abstract
Vaginal candidiasis is a common disorder in women of childbearing age, caused primarily by the dimorphic fungus Candida albicans. Since C. albicans is a normal commensal of the vaginal mucosa, a long-standing question is how the fungus switches from being a harmless commensal to a virulent pathogen. Work with human subjects and in mouse disease models suggests that host inflammatory processes drive the onset of symptomatic infection. Fungal cell wall molecules can induce inflammation through activation of epithelial and immune receptors that trigger pro-inflammatory cytokines and chemokines, but pathogenic fungi can evade recognition by masking these molecules. Knowledge about which cell wall epitopes are available for immune recognition during human infection could implicate specific ligands and receptors in the symptoms of vaginal candidiasis. To address this important gap, we directly probed the surface of fungi present in fresh vaginal samples obtained both from women with symptomatic Candida vaginitis and from women that are colonized but asymptomatic. We find that the pro-inflammatory cell wall polysaccharide β-glucan is largely masked from immune recognition, especially on yeast. It is only exposed on a small percentage of hyphal cells, where it tends to co-localize with enhanced levels of chitin. Enhanced β-glucan availability is only found in symptomatic patients with strong neutrophil infiltration, implicating neutrophils as a possible driver of these cell wall changes. This is especially interesting because neutrophils were recently shown to be necessary and sufficient to provoke enhanced β-glucan exposure in C. albicans, accompanied by elevated immune responses. Taken together, our data suggest that the architecture of C. albicans cell wall can be altered by environmental stress during vaginal candidiasis.
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Affiliation(s)
- Eva Pericolini
- Department of Medicine, University of Perugia, Perugia, Italy
- Department of Diagnostic, Clinical and Public Health Medicine, University of Modena and Reggio Emilia, Modena, Italy
| | - Stefano Perito
- Department of Medicine, University of Perugia, Perugia, Italy
| | - Anna Castagnoli
- School of Specialization in Microbiology and Virology, University of Modena and Reggio Emilia, Modena, Italy
| | - Elena Gabrielli
- Department of Medicine, University of Perugia, Perugia, Italy
| | | | - Elisabetta Blasi
- Department of Diagnostic, Clinical and Public Health Medicine, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Robert T. Wheeler
- Department of Medicine, University of Perugia, Perugia, Italy
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, United States of America
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, Maine, United States of America
- * E-mail:
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20
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Riquelme M, Aguirre J, Bartnicki-García S, Braus GH, Feldbrügge M, Fleig U, Hansberg W, Herrera-Estrella A, Kämper J, Kück U, Mouriño-Pérez RR, Takeshita N, Fischer R. Fungal Morphogenesis, from the Polarized Growth of Hyphae to Complex Reproduction and Infection Structures. Microbiol Mol Biol Rev 2018; 82:e00068-17. [PMID: 29643171 PMCID: PMC5968459 DOI: 10.1128/mmbr.00068-17] [Citation(s) in RCA: 183] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Filamentous fungi constitute a large group of eukaryotic microorganisms that grow by forming simple tube-like hyphae that are capable of differentiating into more-complex morphological structures and distinct cell types. Hyphae form filamentous networks by extending at their tips while branching in subapical regions. Rapid tip elongation requires massive membrane insertion and extension of the rigid chitin-containing cell wall. This process is sustained by a continuous flow of secretory vesicles that depends on the coordinated action of the microtubule and actin cytoskeletons and the corresponding motors and associated proteins. Vesicles transport cell wall-synthesizing enzymes and accumulate in a special structure, the Spitzenkörper, before traveling further and fusing with the tip membrane. The place of vesicle fusion and growth direction are enabled and defined by the position of the Spitzenkörper, the so-called cell end markers, and other proteins involved in the exocytic process. Also important for tip extension is membrane recycling by endocytosis via early endosomes, which function as multipurpose transport vehicles for mRNA, septins, ribosomes, and peroxisomes. Cell integrity, hyphal branching, and morphogenesis are all processes that are largely dependent on vesicle and cytoskeleton dynamics. When hyphae differentiate structures for asexual or sexual reproduction or to mediate interspecies interactions, the hyphal basic cellular machinery may be reprogrammed through the synthesis of new proteins and/or the modification of protein activity. Although some transcriptional networks involved in such reprogramming of hyphae are well studied in several model filamentous fungi, clear connections between these networks and known determinants of hyphal morphogenesis are yet to be established.
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Affiliation(s)
- Meritxell Riquelme
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| | - Jesús Aguirre
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico
| | - Salomon Bartnicki-García
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Michael Feldbrügge
- Institute for Microbiology, Heinrich Heine University Düsseldorf, Cluster of Excellence on Plant Sciences, Düsseldorf, Germany
| | - Ursula Fleig
- Institute for Functional Genomics of Microorganisms, Heinrich Heine University Düsseldorf, Cluster of Excellence on Plant Sciences, Düsseldorf, Germany
| | - Wilhelm Hansberg
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico
| | - Alfredo Herrera-Estrella
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Irapuato, Mexico
| | - Jörg Kämper
- Karlsruhe Institute of Technology-South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
| | - Ulrich Kück
- Ruhr University Bochum, Lehrstuhl für Allgemeine und Molekulare Botanik, Bochum, Germany
| | - Rosa R Mouriño-Pérez
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| | - Norio Takeshita
- University of Tsukuba, Faculty of Life and Environmental Sciences, Tsukuba, Japan
| | - Reinhard Fischer
- Karlsruhe Institute of Technology-South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
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21
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Liang Y, Xiong W, Steinkellner S, Feng J. Deficiency of the melanin biosynthesis genes SCD1 and THR1 affects sclerotial development and vegetative growth, but not pathogenicity, in Sclerotinia sclerotiorum. Mol Plant Pathol 2018; 19:1444-1453. [PMID: 29024255 PMCID: PMC6638068 DOI: 10.1111/mpp.12627] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 09/02/2017] [Accepted: 10/08/2017] [Indexed: 05/29/2023]
Abstract
The fungus Sclerotinia sclerotiorum is a necrotrophic plant pathogen causing significant damage on a broad range of crops. This fungus produces sclerotia that serve as the long-term survival structures in the life cycle and the primary inoculum in the disease cycle. Melanin plays an important role in protecting mycelia and sclerotia from ultraviolet radiation and other adverse environmental conditions. In this study, two genes, SCD1 encoding a scytalone dehydratase and THR1 encoding a trihydroxynaphthalene reductase, were disrupted by target gene replacement, and their roles in mycelial growth, sclerotial development and fungal pathogenicity were investigated. Phylogenetic analyses indicated that the deduced amino acid sequences of SCD1 and THR1 were similar to the orthologues of Botrytis cinerea. Expression of SCD1 was at higher levels in sclerotia relative to mycelia. THR1 was expressed at similar levels in mycelia and sclerotia at early stages, but was up-regulated in sclerotia at the maturation stage. Disruption of SCD1 or THR1 did not change the pathogenicity of the fungus, but resulted in slower radial growth, less biomass, wider angled hyphal branches, impaired sclerotial development and decreased resistance to ultraviolet light.
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Affiliation(s)
- Yue Liang
- College of Plant ProtectionShenyang Agricultural UniversityShenyangLiaoning 110866China
| | - Wei Xiong
- School of Life SciencesChongqing UniversityChongqing 400045China
| | - Siegrid Steinkellner
- Division of Plant Protection, Department of Crop SciencesUniversity of Natural Resources and Life Sciences ViennaVienna 1190Austria
| | - Jie Feng
- Alberta Plant Health Laboratory, Alberta Agriculture and ForestryEdmontonAlberta T5Y 6H3Canada
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22
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Hommel B, Mukaremera L, Cordero RJB, Coelho C, Desjardins CA, Sturny-Leclère A, Janbon G, Perfect JR, Fraser JA, Casadevall A, Cuomo CA, Dromer F, Nielsen K, Alanio A. Titan cells formation in Cryptococcus neoformans is finely tuned by environmental conditions and modulated by positive and negative genetic regulators. PLoS Pathog 2018; 14:e1006982. [PMID: 29775480 PMCID: PMC5959062 DOI: 10.1371/journal.ppat.1006982] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 03/19/2018] [Indexed: 01/06/2023] Open
Abstract
The pathogenic fungus Cryptococcus neoformans exhibits morphological changes in cell size during lung infection, producing both typical size 5 to 7 μm cells and large titan cells (> 10 μm and up to 100 μm). We found and optimized in vitro conditions that produce titan cells in order to identify the ancestry of titan cells, the environmental determinants, and the key gene regulators of titan cell formation. Titan cells generated in vitro harbor the main characteristics of titan cells produced in vivo including their large cell size (>10 μm), polyploidy with a single nucleus, large vacuole, dense capsule, and thick cell wall. Here we show titan cells derived from the enlargement of progenitor cells in the population independent of yeast growth rate. Change in the incubation medium, hypoxia, nutrient starvation and low pH were the main factors that trigger titan cell formation, while quorum sensing factors like the initial inoculum concentration, pantothenic acid, and the quorum sensing peptide Qsp1p also impacted titan cell formation. Inhibition of ergosterol, protein and nucleic acid biosynthesis altered titan cell formation, as did serum, phospholipids and anti-capsular antibodies in our settings. We explored genetic factors important for titan cell formation using three approaches. Using H99-derivative strains with natural genetic differences, we showed that titan cell formation was dependent on LMP1 and SGF29 genes. By screening a gene deletion collection, we also confirmed that GPR4/5-RIM101, and CAC1 genes were required to generate titan cells and that the PKR1, TSP2, USV101 genes negatively regulated titan cell formation. Furthermore, analysis of spontaneous Pkr1 loss-of-function clinical isolates confirmed the important role of the Pkr1 protein as a negative regulator of titan cell formation. Through development of a standardized and robust in vitro assay, our results provide new insights into titan cell biogenesis with the identification of multiple important factors/pathways.
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Affiliation(s)
- Benjamin Hommel
- Institut Pasteur, Molecular Mycology Unit, Département de Mycologie, Paris, France
- CNRS UMR2000, Paris, France
- Laboratoire de Parasitologie-Mycologie, Hôpital Saint-Louis, Groupe Hospitalier Lariboisière, Saint-Louis, Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Liliane Mukaremera
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Radames J. B. Cordero
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD., United States of America
| | - Carolina Coelho
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD., United States of America
| | | | - Aude Sturny-Leclère
- Institut Pasteur, Molecular Mycology Unit, Département de Mycologie, Paris, France
- CNRS UMR2000, Paris, France
| | - Guilhem Janbon
- Institut Pasteur, Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Paris, France
| | - John R. Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - James A. Fraser
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD., United States of America
| | - Christina A. Cuomo
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Françoise Dromer
- Institut Pasteur, Molecular Mycology Unit, Département de Mycologie, Paris, France
- CNRS UMR2000, Paris, France
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Alexandre Alanio
- Institut Pasteur, Molecular Mycology Unit, Département de Mycologie, Paris, France
- CNRS UMR2000, Paris, France
- Laboratoire de Parasitologie-Mycologie, Hôpital Saint-Louis, Groupe Hospitalier Lariboisière, Saint-Louis, Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD., United States of America
- * E-mail:
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23
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Pan Y, Wei J, Yao C, Reng H, Gao Z. SsSm1, a Cerato-platanin family protein, is involved in the hyphal development and pathogenic process of Sclerotinia sclerotiorum. Plant Sci 2018; 270:37-46. [PMID: 29576085 DOI: 10.1016/j.plantsci.2018.02.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 12/18/2017] [Accepted: 02/02/2018] [Indexed: 05/28/2023]
Abstract
The filamentous fungus Sclerotinia sclerotiorum is an important plant pathogen with a worldwide distribution. It can infect a wide variety of plants, causing serious disease in many types of crops, such as rapeseed, sunflower and soybean. Sclerotinia stem rot caused by this fungus affects main crops and has led to great economic loss. Elicitors are a group of compounds that inspire the host plant to produce an immune response against invading pathogens. This study describes a protein that has high homology with the Trichoderma elicitor Sm1 and was found in the genome of S. sclerotiorum. We named this protein SsSm1. To determine whether this protein has an elicitor function like its homology protein, we constructed a heterologous expression vector for SsSm1 and expressed it in Escherichia coli. The protein of heterologous expression led to the formation of lesions in tobacco that closely resemble hypersensitive response lesions. Transient expression of the encoding gene of SsSm1 in tobacco leaves also caused hypersensitive response. Then, RNA silencing was used to identify the function of SsSm1. The hyphal growth and pathogenicity of silenced transformants were shown to be obviously lagging and branched abnormally. Transformants produced less infection cushions and deformed sclerotiorum. In addition, SsSm1 silencing caused weak tolerance to NaCl, sorbitol and SDS, and the sensitivity of mutants to carbendazim was also significantly decreased. Based on the above results, we speculate that this protein may be related to the development of hyphae, infection cushions and sclerotiorum, but the specific molecular mechanism needs to be studied further.
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Affiliation(s)
- Yuemin Pan
- Department of Plant Pathology, College of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Junjun Wei
- Department of Plant Pathology, College of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Chuanchun Yao
- Anhui Academy of Agricultural Sciences, Hefei 230036, China
| | - Hengxue Reng
- Department of Plant Pathology, College of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Zhimou Gao
- Department of Plant Pathology, College of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
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24
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Dambuza IM, Drake T, Chapuis A, Zhou X, Correia J, Taylor-Smith L, LeGrave N, Rasmussen T, Fisher MC, Bicanic T, Harrison TS, Jaspars M, May RC, Brown GD, Yuecel R, MacCallum DM, Ballou ER. The Cryptococcus neoformans Titan cell is an inducible and regulated morphotype underlying pathogenesis. PLoS Pathog 2018; 14:e1006978. [PMID: 29775474 PMCID: PMC5959070 DOI: 10.1371/journal.ppat.1006978] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 03/16/2018] [Indexed: 02/06/2023] Open
Abstract
Fungal cells change shape in response to environmental stimuli, and these morphogenic transitions drive pathogenesis and niche adaptation. For example, dimorphic fungi switch between yeast and hyphae in response to changing temperature. The basidiomycete Cryptococcus neoformans undergoes an unusual morphogenetic transition in the host lung from haploid yeast to large, highly polyploid cells termed Titan cells. Titan cells influence fungal interaction with host cells, including through increased drug resistance, altered cell size, and altered Pathogen Associated Molecular Pattern exposure. Despite the important role these cells play in pathogenesis, understanding the environmental stimuli that drive the morphological transition, and the molecular mechanisms underlying their unique biology, has been hampered by the lack of a reproducible in vitro induction system. Here we demonstrate reproducible in vitro Titan cell induction in response to environmental stimuli consistent with the host lung. In vitro Titan cells exhibit all the properties of in vivo generated Titan cells, the current gold standard, including altered capsule, cell wall, size, high mother cell ploidy, and aneuploid progeny. We identify the bacterial peptidoglycan subunit Muramyl Dipeptide as a serum compound associated with shift in cell size and ploidy, and demonstrate the capacity of bronchial lavage fluid and bacterial co-culture to induce Titanisation. Additionally, we demonstrate the capacity of our assay to identify established (cAMP/PKA) and previously undescribed (USV101) regulators of Titanisation in vitro. Finally, we investigate the Titanisation capacity of clinical isolates and their impact on disease outcome. Together, these findings provide new insight into the environmental stimuli and molecular mechanisms underlying the yeast-to-Titan transition and establish an essential in vitro model for the future characterization of this important morphotype.
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Affiliation(s)
- Ivy M. Dambuza
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Thomas Drake
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Ambre Chapuis
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Xin Zhou
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Joao Correia
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Leanne Taylor-Smith
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Nathalie LeGrave
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Aberdeen, United Kingdom
- Francis Crick Institute, London, United Kingdom
| | - Tim Rasmussen
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Aberdeen, United Kingdom
- Institut für Biochemie, Universität Würzburg, Wurzburg, Germany
| | - Matthew C. Fisher
- Dpt. Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Tihana Bicanic
- Institute of Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Thomas S. Harrison
- Institute of Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Marcel Jaspars
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Robin C. May
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Gordon D. Brown
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Raif Yuecel
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Donna M. MacCallum
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Elizabeth R. Ballou
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
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25
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Carella P, Gogleva A, Tomaselli M, Alfs C, Schornack S. Phytophthora palmivora establishes tissue-specific intracellular infection structures in the earliest divergent land plant lineage. Proc Natl Acad Sci U S A 2018; 115:E3846-E3855. [PMID: 29615512 DOI: 10.1101/188912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
The expansion of plants onto land was a formative event that brought forth profound changes to the earth's geochemistry and biota. Filamentous eukaryotic microbes developed the ability to colonize plant tissues early during the evolution of land plants, as demonstrated by intimate, symbiosis-like associations in >400 million-year-old fossils. However, the degree to which filamentous microbes establish pathogenic interactions with early divergent land plants is unclear. Here, we demonstrate that the broad host-range oomycete pathogen Phytophthora palmivora colonizes liverworts, the earliest divergent land plant lineage. We show that P. palmivora establishes a complex tissue-specific interaction with Marchantia polymorpha, where it completes a full infection cycle within air chambers of the dorsal photosynthetic layer. Remarkably, P. palmivora invaginates M. polymorpha cells with haustoria-like structures that accumulate host cellular trafficking machinery and the membrane syntaxin MpSYP13B, but not the related MpSYP13A. Our results indicate that the intracellular accommodation of filamentous microbes is an ancient plant trait that is successfully exploited by pathogens like P. palmivora.
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Affiliation(s)
- Philip Carella
- Sainsbury Laboratory, University of Cambridge, CB2 1LR Cambridge, United Kingdom
| | - Anna Gogleva
- Sainsbury Laboratory, University of Cambridge, CB2 1LR Cambridge, United Kingdom
| | - Marta Tomaselli
- Sainsbury Laboratory, University of Cambridge, CB2 1LR Cambridge, United Kingdom
| | - Carolin Alfs
- Sainsbury Laboratory, University of Cambridge, CB2 1LR Cambridge, United Kingdom
| | - Sebastian Schornack
- Sainsbury Laboratory, University of Cambridge, CB2 1LR Cambridge, United Kingdom
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26
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Yu Y, Xiao J, Zhu W, Yang Y, Mei J, Bi C, Qian W, Qing L, Tan W. Ss-Rhs1, a secretory Rhs repeat-containing protein, is required for the virulence of Sclerotinia sclerotiorum. Mol Plant Pathol 2017; 18:1052-1061. [PMID: 27392818 PMCID: PMC6638210 DOI: 10.1111/mpp.12459] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 05/05/2023]
Abstract
Sclerotinia sclerotiorum is a devastating necrotrophic plant pathogen with a worldwide distribution. Cell wall-degrading enzymes and oxalic acid are important to the virulence of this pathogen. Here, we report a novel secretory protein, Ss-Rhs1, which is essential for the virulence of S. sclerotiorum. Ss-Rhs1 is believed to contain a typical signal peptide at the N-terminal and eight rearrangement hotspot (Rhs) repeats. Ss-Rhs1 exhibited a high level of expression at the initial stage of sclerotial development, as well as during the hyphal infection process. Targeted silencing of Ss-Rhs1 resulted in abnormal colony morphology and reduced virulence on host plants. Microscopic observations indicated that Ss-Rhs1-silenced strains exhibited reduced efficiency in compound appressoria formation.
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Affiliation(s)
- Yang Yu
- College of Plant ProtectionSouthwest UniversityChongqingCity400715China
| | - Jifen Xiao
- College of Plant ProtectionSouthwest UniversityChongqingCity400715China
| | - Wenjun Zhu
- College of Biology and Pharmaceutical EngineeringWuhan Polytechnic UniversityWuhanCity430023China
| | - Yuheng Yang
- College of Plant ProtectionSouthwest UniversityChongqingCity400715China
| | - Jiaqin Mei
- College of Agronomy and BiotechnologySouthwest UniversityChongqingCity400715China
| | - Chaowei Bi
- College of Plant ProtectionSouthwest UniversityChongqingCity400715China
| | - Wei Qian
- College of Agronomy and BiotechnologySouthwest UniversityChongqingCity400715China
| | - Ling Qing
- College of Plant ProtectionSouthwest UniversityChongqingCity400715China
| | - Wanzhong Tan
- College of Plant ProtectionSouthwest UniversityChongqingCity400715China
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Woolford CA, Lagree K, Xu W, Aleynikov T, Adhikari H, Sanchez H, Cullen PJ, Lanni F, Andes DR, Mitchell AP. Bypass of Candida albicans Filamentation/Biofilm Regulators through Diminished Expression of Protein Kinase Cak1. PLoS Genet 2016; 12:e1006487. [PMID: 27935965 PMCID: PMC5147786 DOI: 10.1371/journal.pgen.1006487] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/15/2016] [Indexed: 12/17/2022] Open
Abstract
Biofilm formation on implanted medical devices is a major source of lethal invasive infection by Candida albicans. Filamentous growth of this fungus is tied to biofilm formation because many filamentation-associated genes are required for surface adherence. Cell cycle or cell growth defects can induce filamentation, but we have limited information about the coupling between filamentation and filamentation-associated gene expression after cell cycle/cell growth inhibition. Here we identified the CDK activating protein kinase Cak1 as a determinant of filamentation and filamentation-associated gene expression through a screen of mutations that diminish expression of protein kinase-related genes implicated in cell cycle/cell growth control. A cak1diminished expression (DX) strain displays filamentous growth and expresses filamentation-associated genes in the absence of typical inducing signals. In a wild-type background, expression of filamentation-associated genes depends upon the transcription factors Bcr1, Brg1, Efg1, Tec1, and Ume6. In the cak1 DX background, the dependence of filamentation-associated gene expression on each transcription factor is substantially relieved. The unexpected bypass of filamentation-associated gene expression activators has the functional consequence of enabling biofilm formation in the absence of Bcr1, Brg1, Tec1, Ume6, or in the absence of both Brg1 and Ume6. It also enables filamentous cell morphogenesis, though not biofilm formation, in the absence of Efg1. Because these transcription factors are known to have shared target genes, we suggest that cell cycle/cell growth limitation leads to activation of several transcription factors, thus relieving dependence on any one. The ability of the pathogen Candida albicans to grow on surfaces as biofilms is a determinant of infection ability, because biofilms on implanted medical devices seed infections. Biofilm formation by this organism requires growth in the form of filamentous cells and the expression of filamentation-associated genes. Inhibition of cell proliferation can induce filamentous cell formation, as we find here for strains that express greatly reduced levels of the cell cycle regulator Cak1. Surprisingly, biofilm formation occurs independently of many central biofilm regulatory genes when Cak1 levels are reduced. This response to proliferation inhibition may reflect the activation of numerous biofilm regulators, thus relieving the dependence on any one regulator. The stimulation of biofilm formation by proliferation inhibition, a property of many bacterial pathogens as well, may contribute to the limited effectiveness of antimicrobials against biofilms.
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Affiliation(s)
- Carol A. Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Katherine Lagree
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Wenjie Xu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Tatyana Aleynikov
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Hema Adhikari
- Department of Biological Sciences at the University at Buffalo, Buffalo, New York, United States of America
| | - Hiram Sanchez
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Paul J. Cullen
- Department of Biological Sciences at the University at Buffalo, Buffalo, New York, United States of America
| | - Frederick Lanni
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - David R. Andes
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Aaron P. Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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Haghdoost NS, Salehi TZ, Khosravi A, Sharifzadeh A. Antifungal activity and influence of propolis against germ tube formation as a critical virulence attribute by clinical isolates of Candida albicans. J Mycol Med 2016; 26:298-305. [PMID: 27789229 DOI: 10.1016/j.mycmed.2015.11.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Revised: 11/22/2015] [Accepted: 11/22/2015] [Indexed: 01/09/2023]
Abstract
OBJECTIVE The potentiality to switch between yeast and hyphal morphologies plays an important role in the virulence of Candida albicans (C. albicans). The objective of the present study was to evaluate the chemical composition, antifungal activity and influence of propolis upon germ tube formation of C. albicans clinical isolates. METHODS The major compounds of propolis ethanolic extract (PEE) was revealed by gas chromatography-mass spectrometry (GC/MS) analysis. Broth microdilution method was used for determination of minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of this extract. C. albicans isolates were exposed to sub-MIC concentrations of propolis and germ tube reduction percent (GRP) and morphological transition from yeast to filamentous form were monitored microscopically. RESULTS Phenolic compounds, aromatic acids, aliphatic acids, sugars and polycyclic aromatic hydrocarbons were the major compound classes in PEE. Mean of MIC and MFC values of PEE against C. albicans isolates were 360.6μg·mL-1 and 1250.1μg·mL-1, respectively. The increase in concentration led to a significant reduction in germ tube formation, so mean of GRP was 36.7±11.1 and 22±10.1 at concentration of ½ MIC and ¼ MIC of PEE, respectively. CONCLUSIONS In conclusion, the present study indicated that PEE has interesting potential as a therapeutic agent that targets germ tube formation by C. albicans as a critical virulence factor.
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Affiliation(s)
- N S Haghdoost
- Mycology research center, faculty of veterinary medicine, university of Tehran, Tehran, Iran
| | - T Z Salehi
- Department of microbiology and immunology, faculty of veterinary medicine, university of Tehran, Azadi Street, Tehran, Iran.
| | - A Khosravi
- Mycology research center, faculty of veterinary medicine, university of Tehran, Tehran, Iran
| | - A Sharifzadeh
- Mycology research center, faculty of veterinary medicine, university of Tehran, Tehran, Iran
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Liu Z, Moran GP, Sullivan DJ, MacCallum DM, Myers LC. Amplification of TLO Mediator Subunit Genes Facilitate Filamentous Growth in Candida Spp. PLoS Genet 2016; 12:e1006373. [PMID: 27741243 PMCID: PMC5065183 DOI: 10.1371/journal.pgen.1006373] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/19/2016] [Indexed: 01/06/2023] Open
Abstract
Filamentous growth is a hallmark of C. albicans pathogenicity compared to less-virulent ascomycetes. A multitude of transcription factors regulate filamentous growth in response to specific environmental cues. Our work, however, suggests the evolutionary history of C. albicans that resulted in its filamentous growth plasticity may be tied to a change in the general transcription machinery rather than transcription factors and their specific targets. A key genomic difference between C. albicans and its less-virulent relatives, including its closest relative C. dubliniensis, is the unique expansion of the TLO (TeLOmere-associated) gene family in C. albicans. Individual Tlo proteins are fungal-specific subunits of Mediator, a large multi-subunit eukaryotic transcriptional co-activator complex. This amplification results in a large pool of ‘free,’ non-Mediator associated, Tlo protein present in C. albicans, but not in C. dubliniensis or other ascomycetes with attenuated virulence. We show that engineering a large ‘free’ pool of the C. dubliniensis Tlo2 (CdTlo2) protein in C. dubliniensis, through overexpression, results in a number of filamentation phenotypes typically associated only with C. albicans. The amplitude of these phenotypes is proportional to the amount of overexpressed CdTlo2 protein. Overexpression of other C. dubliniensis and C. albicans Tlo proteins do result in these phenotypes. Tlo proteins and their orthologs contain a Mediator interaction domain, and a potent transcriptional activation domain. Nuclear localization of the CdTlo2 activation domain, facilitated naturally by the Tlo Mediator binding domain or artificially through an appended nuclear localization signal, is sufficient for the CdTlo2 overexpression phenotypes. A C. albicans med3 null mutant causes multiple defects including the inability to localize Tlo proteins to the nucleus and reduced virulence in a murine systemic infection model. Our data supports a model in which the activation domain of ‘free’ Tlo protein competes with DNA bound transcription factors for targets that regulate key aspects of C. albicans cell physiology. The ascomycete fungus Candida albicans is a leading cause of hospital-acquired bloodstream infections in the United States. Due to limited anti-fungal drug options, there is an approximately 40% mortality rate and over 10,000 deaths per year associated with systemic C. albicans infections. It is unknown why C. albicans is the primary cause of systemic Candidiasis, versus related ascomycetes such as Candida dubliniensis. The genomes of C. albicans and C. dubliniensis are remarkably similar, yet C. dubliniensis has reduced virulence and exhibits less phenotypic plasticity. A striking genomic difference between the fungi is the amplification of the TLO (TeLOmere-associated) genes in C. albicans, which encode a fungal-specific subunit of the Mediator co-activator complex. Amplification results in a large pool of ‘free’ (non-Mediator associated) Tlo protein in C. albicans that is absent in C. dubliniensis. Engineering a large ‘free’ pool of Tlo protein in C. dubliniensis, through overexpression, results in phenotypes common in C. albicans, yet typically absent in C. dubliniensis. Tlo proteins contain a potent transcriptional activation domain. Nuclear localization of the Tlo activation domain is necessary and sufficient for the TLO overexpression phenotypes. This study provides a mechanistic explanation for how TLO amplification in C. albicans may enhance its virulence.
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Affiliation(s)
- Zhongle Liu
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Gary P. Moran
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Dublin, Ireland
| | - Derek J. Sullivan
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Dublin, Ireland
| | - Donna M. MacCallum
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Lawrence C. Myers
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Department of Medical Education, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- * E-mail:
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Ding Z, Li M, Sun F, Xi P, Sun L, Zhang L, Jiang Z. Mitogen-activated protein kinases are associated with the regulation of physiological traits and virulence in Fusarium oxysporum f. sp. cubense. PLoS One 2015; 10:e0122634. [PMID: 25849862 PMCID: PMC4388850 DOI: 10.1371/journal.pone.0122634] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/23/2015] [Indexed: 01/09/2023] Open
Abstract
Fusarium oxysporum f. sp. cubense (FOC) is an important soil-borne fungal pathogen causing devastating vascular wilt disease of banana plants and has become a great concern threatening banana production worldwide. However, little information is known about the molecular mechanisms that govern the expression of virulence determinants of this important fungal pathogen. In this study, we showed that null mutation of three mitogen-activated protein (MAP) kinase genes, designated as FoSlt2, FoMkk2 and FoBck1, respectively, led to substantial attenuation in fungal virulence on banana plants. Transcriptional analysis revealed that the MAP kinase signaling pathway plays a key role in regulation of the genes encoding production of chitin, peroxidase, beauvericin and fusaric acid. Biochemical analysis further confirmed the essential role of MAP kinases in modulating the production of fusaric acid, which was a crucial phytotoxin in accelerating development of Fusarium wilt symptoms in banana plants. Additionally, we found that the MAP kinase FoSlt2 was required for siderophore biosynthesis under iron-depletion conditions. Moreover, disruption of the MAP kinase genes resulted in abnormal hypha and increased sensitivity to Congo Red, Calcofluor White and H2O2. Taken together, these results depict the critical roles of MAP kinases in regulation of FOC physiology and virulence.
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Affiliation(s)
- Zhaojian Ding
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
| | - Minhui Li
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
| | - Fei Sun
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
| | - Pinggen Xi
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
| | - Longhua Sun
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
| | - Lianhui Zhang
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
- * E-mail: (ZDJ); (LHZ)
| | - Zide Jiang
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
- * E-mail: (ZDJ); (LHZ)
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Uloth MB, Clode PL, You MP, Barbetti MJ. Calcium oxalate crystals: an integral component of the Sclerotinia sclerotiorum/Brassica carinata pathosystem. PLoS One 2015; 10:e0122362. [PMID: 25816022 PMCID: PMC4376799 DOI: 10.1371/journal.pone.0122362] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/10/2015] [Indexed: 12/22/2022] Open
Abstract
Oxalic acid is an important virulence factor for disease caused by the fungal necrotrophic pathogen Sclerotinia sclerotiorum, yet calcium oxalate (CaOx) crystals have not been widely reported. B. carinata stems were infected with S. sclerotiorum and observed using light microscopy. Six hours post inoculation (hpi), CaOx crystals were evident on 46% of stem sections and by 72 hpi on 100%, demonstrating that the secretion of oxalic acid by S. sclerotiorum commences before hyphal penetration. This is the first time CaOx crystals have been reported on B. carinata infected with S. sclerotiorum. The shape of crystals varied as infection progressed. Long tetragonal rods were dominant 12 hpi (68% of crystal-containing samples), but by 72 hpi, 50% of stems displayed bipyramidal crystals, and only 23% had long rods. Scanning electron microscopy from 24 hpi revealed CaOx crystals in all samples, ranging from tiny irregular crystals (< 0.5 μm) to large (up to 40 μm) highly organized arrangements. Crystal morphology encompassed various forms, including tetragonal prisms, oval plates, crystal sand, and druses. Large conglomerates of CaOx crystals were observed in the hyphal mass 72 hpi and these are proposed as a strategy of the fungus to hold and detoxify Ca2+ions. The range of crystal morphologies suggests that S. sclerotiorum growth and infection controls the form taken by CaOx crystals.
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Affiliation(s)
- Margaret B. Uloth
- School of Plant Biology, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Peta L. Clode
- Centre for Microscopy, Characterisation and Analysis, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Ming Pei You
- School of Plant Biology and The UWA Institute of Agriculture, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Martin J. Barbetti
- School of Plant Biology and The UWA Institute of Agriculture, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
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Affiliation(s)
- Gregory M. Gauthier
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail:
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33
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Wartenberg A, Linde J, Martin R, Schreiner M, Horn F, Jacobsen ID, Jenull S, Wolf T, Kuchler K, Guthke R, Kurzai O, Forche A, d'Enfert C, Brunke S, Hube B. Microevolution of Candida albicans in macrophages restores filamentation in a nonfilamentous mutant. PLoS Genet 2014; 10:e1004824. [PMID: 25474009 PMCID: PMC4256171 DOI: 10.1371/journal.pgen.1004824] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 10/15/2014] [Indexed: 11/30/2022] Open
Abstract
Following antifungal treatment, Candida albicans, and other human pathogenic fungi can undergo microevolution, which leads to the emergence of drug resistance. However, the capacity for microevolutionary adaptation of fungi goes beyond the development of resistance against antifungals. Here we used an experimental microevolution approach to show that one of the central pathogenicity mechanisms of C. albicans, the yeast-to-hyphae transition, can be subject to experimental evolution. The C. albicans cph1Δ/efg1Δ mutant is nonfilamentous, as central signaling pathways linking environmental cues to hyphal formation are disrupted. We subjected this mutant to constant selection pressure in the hostile environment of the macrophage phagosome. In a comparatively short time-frame, the mutant evolved the ability to escape macrophages by filamentation. In addition, the evolved mutant exhibited hyper-virulence in a murine infection model and an altered cell wall composition compared to the cph1Δ/efg1Δ strain. Moreover, the transcriptional regulation of hyphae-associated, and other pathogenicity-related genes became re-responsive to environmental cues in the evolved strain. We went on to identify the causative missense mutation via whole genome- and transcriptome-sequencing: a single nucleotide exchange took place within SSN3 that encodes a component of the Cdk8 module of the Mediator complex, which links transcription factors with the general transcription machinery. This mutation was responsible for the reconnection of the hyphal growth program with environmental signals in the evolved strain and was sufficient to bypass Efg1/Cph1-dependent filamentation. These data demonstrate that even central transcriptional networks can be remodeled very quickly under appropriate selection pressure. Pathogenic microbes often evolve complex traits to adapt to their respective hosts, and this evolution is ongoing: for example, microorganisms are developing resistance to antimicrobial compounds in the clinical setting. The ability of the common human pathogenic fungus, Candida albicans, to switch from yeast to hyphal (filamentous) growth is considered a central virulence attribute. For example, hyphal formation allows C. albicans to escape from macrophages following phagocytosis. A well-investigated signaling network integrates different environmental cues to induce and maintain hyphal growth. In fact, deletion of two central transcription factors in this network results in a mutant that is both nonfilamentous and avirulent. We used experimental evolution to study the adaptation capability of this mutant by continuous co-incubation within macrophages. We found that this selection regime led to a relatively rapid re-connection of signaling between environmental cues and the hyphal growth program. Indeed, the evolved mutant regained the ability to filament and its virulence in vivo. This bypass of central transcription factors was based on a single nucleotide exchange in a gene encoding a component of the general transcription regulation machinery. Our results show that even a complex regulatory network, such as the transcriptional network which governs hyphal growth, can be remodeled via microevolution.
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Affiliation(s)
- Anja Wartenberg
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Jörg Linde
- Research Group Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Ronny Martin
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology –Hans Knoell Institute, Jena, Germany
| | - Maria Schreiner
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Fabian Horn
- Research Group Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Ilse D. Jacobsen
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Sabrina Jenull
- Medical University Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Vienna, Austria
| | - Thomas Wolf
- Research Group Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Karl Kuchler
- Medical University Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Vienna, Austria
| | - Reinhard Guthke
- Research Group Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Oliver Kurzai
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology –Hans Knoell Institute, Jena, Germany
| | - Anja Forche
- Department of Biology, Bowdoin College, Brunswick, Maine, United States of America
| | - Christophe d'Enfert
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France
- INRA, USC2019, Paris, France
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
- Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), Universitätsklinikum Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
- Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), Universitätsklinikum Jena, Germany
- Friedrich Schiller University, Jena, Germany
- * E-mail:
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Zhao P, Zhao YL, Jin Y, Zhang T, Guo HS. Colonization process of Arabidopsis thaliana roots by a green fluorescent protein-tagged isolate of Verticillium dahliae. Protein Cell 2014; 5:94-8. [PMID: 24481631 PMCID: PMC3956967 DOI: 10.1007/s13238-013-0009-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- Pan Zhao
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yun-Long Zhao
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yun Jin
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Tao Zhang
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Hui-Shan Guo
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
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Haran J, Boyle H, Hokamp K, Yeomans T, Liu Z, Church M, Fleming AB, Anderson MZ, Berman J, Myers LC, Sullivan DJ, Moran GP. Telomeric ORFs (TLOs) in Candida spp. Encode mediator subunits that regulate distinct virulence traits. PLoS Genet 2014; 10:e1004658. [PMID: 25356803 PMCID: PMC4214616 DOI: 10.1371/journal.pgen.1004658] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 08/11/2014] [Indexed: 11/18/2022] Open
Abstract
The TLO genes are a family of telomere-associated ORFs in the fungal pathogens Candida albicans and C. dubliniensis that encode a subunit of the Mediator complex with homology to Med2. The more virulent pathogen C. albicans has 15 copies of the gene whereas the less pathogenic species C. dubliniensis has only two (CdTLO1 and CdTLO2). In this study we used C. dubliniensis as a model to investigate the role of TLO genes in regulating virulence and also to determine whether TLO paralogs have evolved to regulate distinct functions. A C. dubliniensis tlo1Δ/tlo2Δ mutant is unable to form true hyphae, has longer doubling times in galactose broth, is more susceptible to oxidative stress and forms increased levels of biofilm. Transcript profiling of the tlo1Δ/tlo2Δ mutant revealed increased expression of starvation responses in rich medium and retarded expression of hypha-induced transcripts in serum. ChIP studies indicated that Tlo1 binds to many ORFs including genes that exhibit high and low expression levels under the conditions analyzed. The altered expression of these genes in the tlo1Δ/tlo2Δ null mutant indicates roles for Tlo proteins in transcriptional activation and repression. Complementation of the tlo1Δ/tlo2Δ mutant with TLO1, but not TLO2, restored wild-type filamentous growth, whereas only TLO2 fully suppressed biofilm growth. Complementation with TLO1 also had a greater effect on doubling times in galactose broth. The different abilities of TLO1 and TLO2 to restore wild-type functions was supported by transcript profiling studies that showed that only TLO1 restored expression of hypha-specific genes (UME6, SOD5) and galactose utilisation genes (GAL1 and GAL10), whereas TLO2 restored repression of starvation-induced gene transcription. Thus, Tlo/Med2 paralogs encoding Mediator subunits regulate different virulence properties in Candida spp. and their expansion may account for the increased adaptability of C. albicans relative to other Candida species.
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Affiliation(s)
- John Haran
- Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Hannah Boyle
- Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Karsten Hokamp
- School of Genetics and Microbiology, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Tim Yeomans
- Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Zhongle Liu
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Michael Church
- School of Genetics and Microbiology, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Alastair B. Fleming
- School of Genetics and Microbiology, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Matthew Z. Anderson
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Judith Berman
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel
| | - Lawrence C. Myers
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Derek J. Sullivan
- Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
- * E-mail: (DJS); (GPM)
| | - Gary P. Moran
- Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
- * E-mail: (DJS); (GPM)
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Abstract
Penicillium marneffei, one of the most important thermal dimorphic fungi, is a severe threat to the life of immunocompromised patients. However, the pathogenic mechanisms of P. marneffei remain largely unknown. In this work, we developed a model host by using nematode Caenorhabditis elegans to investigate the virulence of P. marneffei. Using two P. marneffei clinical isolate strains 570 and 486, we revealed that in both liquid and solid media, the ingestion of live P. marneffei was lethal to C. elegans (P<0.001). Meanwhile, our results showed that the strain 570, which can produce red pigment, had stronger pathogenicity in C. elegans than the strain 486, which can’t produce red pigment (P<0.001). Microscopy showed the formation of red pigment and hyphae within C. elegans after incubation with P. marneffei for 4 h, which are supposed to be two contributors in nematodes killing. In addition, we used C. elegans as an in vivo model to evaluate different antifungal agents against P. marneffei, and found that antifungal agents including amphotericin B, terbinafine, fluconazole, itraconazole and voriconazole successfully prolonged the survival of nematodesinfected by P. marneffei. Overall, this alternative model host can provide us an easy tool to study the virulence of P. marneffei and screen antifungal agents.
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Affiliation(s)
- Xiaowen Huang
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
- Department of Dermatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Dedong Li
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
- School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Liyan Xi
- Department of Dermatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- * E-mail: (LX); (EM)
| | - Eleftherios Mylonakis
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
- * E-mail: (LX); (EM)
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Vylkova S, Lorenz MC. Modulation of phagosomal pH by Candida albicans promotes hyphal morphogenesis and requires Stp2p, a regulator of amino acid transport. PLoS Pathog 2014; 10:e1003995. [PMID: 24626429 PMCID: PMC3953444 DOI: 10.1371/journal.ppat.1003995] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 01/30/2014] [Indexed: 12/23/2022] Open
Abstract
Candida albicans, the most important fungal pathogen of humans, has a unique interaction with macrophages in which phagocytosis induces a switch from the yeast to hyphal form, allowing it to escape by rupturing the immune cell. While a variety of factors induce this switch in vitro, including neutral pH, it is not clear what triggers morphogenesis within the macrophage where the acidic environment should inhibit this transition. In vitro, C. albicans grown in similar conditions in which amino acids are the primary carbon source generate large quantities of ammonia to raise the extracellular pH and induce the hyphal switch. We show here that C. albicans cells neutralize the macrophage phagosome and that neutral pH is a key inducer of germination in phagocytosed cells by using a mutant lacking STP2, a transcription factor that regulates the expression of multiple amino acid permeases, that is completely deficient in alkalinization in vitro. Phagocytosed stp2Δ mutant cells showed significant reduction in hypha formation and escaped from macrophages less readily compared to wild type cells; as a result stp2Δ mutant cells were killed at a higher rate and caused less damage to RAW264.7 macrophages. Stp2p-regulated import leads to alkalinization of the phagosome, since the majority of the wild type cells fail to co-localize with acidophilic dyes, whereas the stp2Δ mutant cells were located in acidic phagosomes. Furthermore, stp2Δ mutant cells were able to form hyphae and escape from neutral phagosomes, indicating that the survival defect in these cells was pH dependent. Finally, these defects are reflected in an attenuation of virulence in a mouse model of disseminated candidiasis. Altogether our results suggest that C. albicans utilizes amino acids to promote neutralization of the phagosomal pH, hyphal morphogenesis, and escape from macrophages. The innate immune system represents a key barrier that fungal pathogens such as Candida albicans must overcome in order to disseminate through the host. C. albicans cells phagocytosed by macrophages initiate a complex program that involves a large-scale reprogramming of metabolism and transcription and results in the switch to a hyphal form that can penetrate and kill the macrophage. Though a number of signals are known to induce this morphological transition in vitro, what does so following phagocytosis has been unclear. We previously showed that C. albicans rapidly neutralizes acidic, nutrient-poor media that resembles the phagolysosome and that this is deficient in mutants impaired in amino acid import due to a mutation in STP2. In this paper, we investigate whether this happens within the macrophage as well. We show here that, in contrast to wild-type cells, stp2Δ mutants occupy an acidic phagosome and are unable to initiate hyphal differentiation. Because of this, they are more sensitive to killing and do less damage to the macrophages than cells that can neutralize the phagolysosome. We conclude that alteration of phagosomal pH is an important virulence adaptation in this species.
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Affiliation(s)
- Slavena Vylkova
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center, Houston, Texas, United States of America
| | - Michael C. Lorenz
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center, Houston, Texas, United States of America
- * E-mail:
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Abstract
Specialized Candida albicans cell surface proteins called adhesins mediate binding of the fungus to host cells. The mammalian transglutaminase (TG) substrate and adhesin, Hyphal wall protein 1 (Hwp1), is expressed on the hyphal form of C. albicans where it mediates fungal adhesion to epithelial cells. Hwp1 is also required for biofilm formation and mating thus the protein functions in both fungal-host and self-interactions. Hwp1 is required for full virulence of C. albicans in murine models of disseminated candidiasis and of esophageal candidiasis. Previous studies correlated TG activity on the surface of oral epithelial cells, produced by epithelial TG (TG1), with tight binding of C. albicans via Hwp1 to the host cell surfaces. However, the contribution of other Tgs, specifically tissue TG (TG2), to disseminated candidiasis mediated by Hwp1 was not known. A newly created hwp1 null strain in the wild type SC5314 background was as virulent as the parental strain in C57BL/6 mice, and virulence was retained in C57BL/6 mice deleted for Tgm2 (TG2). Further, the hwp1 null strains displayed modestly reduced virulence in BALB/c mice as did strain DD27-U1, an independently created hwp1Δ/Δ in CAI4 corrected for its ura3Δ defect at the URA3 locus. Hwp1 was still needed to produce wild type biofilms, and persist on murine tongues in an oral model of oropharyngeal candidiasis consistent with previous studies by us and others. Finally, lack of Hwp1 affected the translocation of C. albicans from the mouse intestine into the bloodstream of mice. Together, Hwp1 appears to have a minor role in disseminated candidiasis, independent of tissue TG, but a key function in host- and self-association to the surface of oral mucosa.
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Affiliation(s)
- Janet F. Staab
- Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Kausik Datta
- Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Peter Rhee
- Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
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39
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Abstract
Candida albicans is an opportunistic and polymorphic fungal pathogen that causes mucosal, disseminated and invasive infections in humans. Transition from the yeast form to the hyphal form is one of the key virulence factors in C. albicans contributing to macrophage evasion, tissue invasion and biofilm formation. Nontoxic small molecules that inhibit C. albicans yeast-to-hypha conversion and hyphal growth could represent a valuable source for understanding pathogenic fungal morphogenesis, identifying drug targets and serving as templates for the development of novel antifungal agents. Here, we have identified the triterpenoid saponin family of gymnemic acids (GAs) as inhibitor of C. albicans morphogenesis. GAs were isolated and purified from Gymnema sylvestre leaves, the Ayurvedic traditional medicinal plant used to treat diabetes. Purified GAs had no effect on the growth and viability of C. albicans yeast cells but inhibited its yeast-to-hypha conversion under several hypha-inducing conditions, including the presence of serum. Moreover, GAs promoted the conversion of C. albicans hyphae into yeast cells under hypha inducing conditions. They also inhibited conidial germination and hyphal growth of Aspergillus sp. Finally, GAs inhibited the formation of invasive hyphae from C. albicans-infected Caenorhabditis elegans worms and rescued them from killing by C. albicans. Hence, GAs could be useful for various antifungal applications due to their traditional use in herbal medicine.
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Affiliation(s)
- Govindsamy Vediyappan
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France
- INRA, USC2019, Paris, France
- * E-mail:
| | - Vincent Dumontet
- CNRS, Institut de Chimie des Substances Naturelles, Centre de Recherche de Gif, Gif-sur-Yvette, France
| | - Franck Pelissier
- CNRS, Institut de Chimie des Substances Naturelles, Centre de Recherche de Gif, Gif-sur-Yvette, France
| | - Christophe d’Enfert
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France
- INRA, USC2019, Paris, France
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Raut JS, Shinde RB, Chauhan NM, Karuppayil SM. Terpenoids of plant origin inhibit morphogenesis, adhesion, and biofilm formation by Candida albicans. Biofouling 2013; 29:87-96. [PMID: 23216018 DOI: 10.1080/08927014.2012.749398] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Biofilm-related infections caused by Candida albicans and associated drug resistant micro-organisms are serious problems for immunocompromised populations. Molecules which can prevent or remove biofilms are needed. Twenty-eight terpenoids of plant origin were analysed for their activity against growth, virulence attributes, and biofilms of C. albicans. Eighteen molecules exhibited minimum inhibitory concentrations of <2 mg ml(-1) for planktonic growth. Selected molecules inhibited yeast to hyphal dimorphism at low concentrations (0.031-0.5 mg ml(-1)), while adhesion to a solid surface was prevented at 0.5-2 mg ml(-1). Treatment with 14 terpenoids resulted in significant (p < 0.05) inhibition of biofilm formation, and of these, linalool, nerol, isopulegol, menthol, carvone, α-thujone, and farnesol exhibited biofilm-specific activity. Eight terpenoids were identified as inhibitors of mature biofilms. This study demonstrated the antibiofilm potential of terpenoids, which need to be further explored as therapeutic strategy against biofilm associated infections of C. albicans.
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Affiliation(s)
- Jayant S Raut
- DST-FIST & UGC-SAP School of Life Sciences, SRTM University, Nanded, 431 606, MS, India
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41
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Cheng Y, Zhang H, Yao J, Wang X, Xu J, Han Q, Wei G, Huang L, Kang Z. Characterization of non-host resistance in broad bean to the wheat stripe rust pathogen. BMC Plant Biol 2012; 12:96. [PMID: 22716957 PMCID: PMC3487988 DOI: 10.1186/1471-2229-12-96] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 06/07/2012] [Indexed: 05/23/2023]
Abstract
BACKGROUND Non-host resistance (NHR) confers plant species immunity against the majority of microbial pathogens and represents the most robust and durable form of plant resistance in nature. As one of the main genera of rust fungi with economic and biological importance, Puccinia infects almost all cereals but is unable to cause diseases on legumes. Little is known about the mechanism of this kind of effective defense in legumes to these non-host pathogens. RESULTS In this study, the basis of NHR in broad bean (Vicia faba L.) against the wheat stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst), was characterized. No visible symptoms were observed on broad bean leaves inoculated with Pst. Microscopic observations showed that successful location of stomata and haustoria formation were significantly reduced in Pst infection of broad bean. Attempted infection induced the formation of papillae, cell wall thickening, production of reactive oxygen species, callose deposition and accumulation of phenolic compounds in plant cell walls. The few Pst haustoria that did form in broad bean cells were encased in reactive oxygen and callose materials and those cells elicited cell death. Furthermore, a total of seven defense-related genes were identified and found to be up-regulated during the Pst infection. CONCLUSIONS The results indicate that NHR in broad bean against Pst results from a continuum of layered defenses, including basic incompatibility, structural and chemical strengthening of cell wall, posthaustorial hypersensitive response and induction of several defense-related genes, demonstrating the multi-layered feature of NHR. This work also provides useful information for further determination of resistance mechanisms in broad bean to rust fungi, especially the adapted important broad bean rust pathogen, Uromyces viciae-fabae, because of strong similarity and association between NHR of plants to unadapted pathogens and basal resistance of plants to adapted pathogens.
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Affiliation(s)
- Yulin Cheng
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China
| | - Hongchang Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China
| | - Juanni Yao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China
| | - Xiaojie Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China
| | - Jinrong Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Qingmei Han
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China
| | - Guorong Wei
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China
| | - Lili Huang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China
| | - Zhensheng Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China
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42
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Brown NA, Antoniw J, Hammond-Kosack KE. The predicted secretome of the plant pathogenic fungus Fusarium graminearum: a refined comparative analysis. PLoS One 2012; 7:e33731. [PMID: 22493673 PMCID: PMC3320895 DOI: 10.1371/journal.pone.0033731] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 02/16/2012] [Indexed: 11/18/2022] Open
Abstract
The fungus Fusarium graminearum forms an intimate association with the host species wheat whilst infecting the floral tissues at anthesis. During the prolonged latent period of infection, extracellular communication between live pathogen and host cells must occur, implying a role for secreted fungal proteins. The wheat cells in contact with fungal hyphae subsequently die and intracellular hyphal colonisation results in the development of visible disease symptoms. Since the original genome annotation analysis was done in 2007, which predicted the secretome using TargetP, the F. graminearum gene call has changed considerably through the combined efforts of the BROAD and MIPS institutes. As a result of the modifications to the genome and the recent findings that suggested a role for secreted proteins in virulence, the F. graminearum secretome was revisited. In the current study, a refined F. graminearum secretome was predicted by combining several bioinformatic approaches. This strategy increased the probability of identifying truly secreted proteins. A secretome of 574 proteins was predicted of which 99% was supported by transcriptional evidence. The function of the annotated and unannotated secreted proteins was explored. The potential role(s) of the annotated proteins including, putative enzymes, phytotoxins and antifungals are discussed. Characterisation of the unannotated proteins included the analysis of Pfam domains and features associated with known fungal effectors, for example, small size, cysteine-rich and containing internal amino acid repeats. A comprehensive comparative genomic analysis involving 57 fungal and oomycete genomes revealed that only a small number of the predicted F. graminearum secreted proteins can be considered to be either species or sequenced strain specific.
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Affiliation(s)
- Neil A Brown
- Centre for Sustainable Pest and Disease Management, Department of Plant Pathology and Microbiology, Rothamsted Research, Harpenden, Hertfordshire, United Kingdom
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43
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Kleemann J, Rincon-Rivera LJ, Takahara H, Neumann U, van Themaat EVL, van der Does HC, Hacquard S, Stüber K, Will I, Schmalenbach W, Schmelzer E, O'Connell RJ. Sequential delivery of host-induced virulence effectors by appressoria and intracellular hyphae of the phytopathogen Colletotrichum higginsianum. PLoS Pathog 2012; 8:e1002643. [PMID: 22496661 PMCID: PMC3320591 DOI: 10.1371/journal.ppat.1002643] [Citation(s) in RCA: 224] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 02/29/2012] [Indexed: 12/29/2022] Open
Abstract
Phytopathogens secrete effector proteins to manipulate their hosts for effective colonization. Hemibiotrophic fungi must maintain host viability during initial biotrophic growth and elicit host death for subsequent necrotrophic growth. To identify effectors mediating these opposing processes, we deeply sequenced the transcriptome of Colletotrichum higginsianum infecting Arabidopsis. Most effector genes are host-induced and expressed in consecutive waves associated with pathogenic transitions, indicating distinct effector suites are deployed at each stage. Using fluorescent protein tagging and transmission electron microscopy-immunogold labelling, we found effectors localised to stage-specific compartments at the host-pathogen interface. In particular, we show effectors are focally secreted from appressorial penetration pores before host invasion, revealing new levels of functional complexity for this fungal organ. Furthermore, we demonstrate that antagonistic effectors either induce or suppress plant cell death. Based on these results we conclude that hemibiotrophy in Colletotrichum is orchestrated through the coordinated expression of antagonistic effectors supporting either cell viability or cell death.
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Affiliation(s)
- Jochen Kleemann
- Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | - Linda J. Rincon-Rivera
- Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | - Hiroyuki Takahara
- Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | - Ulla Neumann
- Central Microscopy Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | - Emiel Ver Loren van Themaat
- Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | - H. Charlotte van der Does
- Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | - Stéphane Hacquard
- Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | - Kurt Stüber
- Max Planck Genome Centre Cologne, Cologne, Germany
| | - Isa Will
- Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | - Wolfgang Schmalenbach
- Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | - Elmon Schmelzer
- Central Microscopy Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | - Richard J. O'Connell
- Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
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Kong LA, Yang J, Li GT, Qi LL, Zhang YJ, Wang CF, Zhao WS, Xu JR, Peng YL. Different chitin synthase genes are required for various developmental and plant infection processes in the rice blast fungus Magnaporthe oryzae. PLoS Pathog 2012; 8:e1002526. [PMID: 22346755 PMCID: PMC3276572 DOI: 10.1371/journal.ppat.1002526] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 12/24/2011] [Indexed: 11/18/2022] Open
Abstract
Chitin is a major component of fungal cell wall and is synthesized by chitin synthases (Chs). Plant pathogenic fungi normally have multiple chitin synthase genes. To determine their roles in development and pathogenesis, we functionally characterized all seven CHS genes in Magnaporthe oryzae. Three of them, CHS1, CHS6, and CHS7, were found to be important for plant infection. While the chs6 mutant was non-pathogenic, the chs1 and chs7 mutants were significantly reduced in virulence. CHS1 plays a specific role in conidiogenesis, an essential step for natural infection cycle. Most of chs1 conidia had no septum and spore tip mucilage. The chs6 mutant was reduced in hyphal growth and conidiation. It failed to penetrate and grow invasively in plant cells. The two MMD-containing chitin synthase genes, CHS5 and CHS6, have a similar expression pattern. Although deletion of CHS5 had no detectable phenotype, the chs5 chs6 double mutant had more severe defects than the chs6 mutant, indicating that they may have overlapping functions in maintaining polarized growth in vegetative and invasive hyphae. Unlike the other CHS genes, CHS7 has a unique function in appressorium formation. Although it was blocked in appressorium formation by germ tubes on artificial hydrophobic surfaces, the chs7 mutant still produced melanized appressoria by hyphal tips or on plant surfaces, indicating that chitin synthase genes have distinct impacts on appressorium formation by hyphal tip and germ tube. The chs7 mutant also was defective in appressorium penetration and invasive growth. Overall, our results indicate that individual CHS genes play diverse roles in hyphal growth, conidiogenesis, appressorium development, and pathogenesis in M. oryzae, and provided potential new leads in the control of this devastating pathogen by targeting specific chitin synthases. Chitin is one of the major components of cell wall that plays vital roles in hyphal tip growth and fungal morphogenesis. Biosynthesis of chitin is catalyzed by chitin synthases, a well-known fungicide target. However, systematic characterization of chitin synthase genes has not yet been reported in plant pathogenic ascomycetes. To determine their roles in development and pathogenesis, in this study we functionally characterized all the seven chitin synthase genes (CHS1-CHS7) in Magnaporthe oryzae, a model for studying fungal development and pathogenesis. While CHS2, CHS3, CHS4, and CHS5 are dispensable for plant infection, CHS6 is essential for pathogenesis. The chs6 mutant failed to penetrate plant cells and develop infectious hyphae. Two other chitin synthase genes, CHS1 and CHS7, also are important for virulence. The chs1 and chs7 mutants caused only rare lesions on rice seedlings. Other than plant infection, CHS1 and CHS7 also play specific roles during conidiogenesis and appressorium formation, respectively. Interestingly, the chs7 mutant was blocked in appressorium formation by germ tubes on artificial hydrophobic surfaces but was normal by hyphal tips and on plant surfaces. Different chitin synthase genes may be involved during appressorium formation by different fungal tissues or on different surfaces in M. oryzae.
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Affiliation(s)
- Ling-An Kong
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
- Purdue-NWAFU Joint Research Center and State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Jun Yang
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
| | - Guo-Tian Li
- Purdue-NWAFU Joint Research Center and State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Lin-Lu Qi
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
| | - Yu-Jun Zhang
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
| | - Chen-Fang Wang
- College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Wen-Sheng Zhao
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
| | - Jin-Rong Xu
- Purdue-NWAFU Joint Research Center and State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- * E-mail: (JRX); (YLP)
| | - You-Liang Peng
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
- * E-mail: (JRX); (YLP)
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Zhang H, Wang C, Cheng Y, Wang X, Li F, Han Q, Xu J, Chen X, Huang L, Wei G, Kang Z. Histological and molecular studies of the non-host interaction between wheat and Uromyces fabae. Planta 2011; 234:979-91. [PMID: 21691848 DOI: 10.1007/s00425-011-1453-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 05/24/2011] [Indexed: 05/26/2023]
Abstract
Non-host resistance (NHR) confers plant species immunity against the majority of microbes. As an important crop, wheat can be damaged by several Puccinia species but is immune to all Uromyces species. Here, we studied the basis of NHR in wheat against the broad bean rust pathogen Uromyces fabae (Uf). In the wheat-Uf interaction, microscopic observations showed that urediospores germinated efficiently on wheat leaves. However, over 98% of the germ tubes failed to form appressoria over stomata. For the few that invaded through stomata, the majority of them failed to penetrate wheat mesophyll cells. At 96 hours after inoculation, less than 4% of the Uf infection units that had entered the mesophyll tissue formed haustoria. Attempted penetration by haustorium mother cells induced the thickening of cell wall and the formation of papillae in plant cells, which arrested the development or growth of Uf penetration pegs. For the Uf haustoria formed in wheat cells, they were encased in callose-like materials and did not elicit hypersensitive response. Localized accumulation of H(2)O(2) were observed in plant cell walls, papillae and encasement of haustoria during the wheat-Uf interaction. Furthermore, quantitative RT-PCR analysis showed that several genes involved in basal resistance and oxidative stress responses were up-regulated during Uf infection. In conclusion, our study revealed the cytological and molecular bases of NHR in wheat against the non-adapted rust fungus Uf, and highlighted the significance of papilla production in the prehaustorial NHR.
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Affiliation(s)
- Hongchang Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University Yangling, Shaanxi, 712100, People's Republic of China
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Pérez-Nadales E, Di Pietro A. The membrane mucin Msb2 regulates invasive growth and plant infection in Fusarium oxysporum. Plant Cell 2011; 23:1171-85. [PMID: 21441438 PMCID: PMC3082261 DOI: 10.1105/tpc.110.075093] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 02/18/2011] [Accepted: 03/08/2011] [Indexed: 05/20/2023]
Abstract
Fungal pathogenicity in plants requires a conserved mitogen-activated protein kinase (MAPK) cascade homologous to the yeast filamentous growth pathway. How this signaling cascade is activated during infection remains poorly understood. In the soil-borne vascular wilt fungus Fusarium oxysporum, the orthologous MAPK Fmk1 (Fusarium MAPK1) is essential for root penetration and pathogenicity in tomato (Solanum lycopersicum) plants. Here, we show that Msb2, a highly glycosylated transmembrane protein, is required for surface-induced phosphorylation of Fmk1 and contributes to a subset of Fmk1-regulated functions related to invasive growth and virulence. Mutants lacking Msb2 share characteristic phenotypes with the Δfmk1 mutant, including defects in cellophane invasion, penetration of the root surface, and induction of vascular wilt symptoms in tomato plants. In contrast with Δfmk1, Δmsb2 mutants were hypersensitive to cell wall targeting compounds, a phenotype that was exacerbated in a Δmsb2 Δfmk1 double mutant. These results suggest that the membrane mucin Msb2 promotes invasive growth and plant infection upstream of Fmk1 while contributing to cell integrity through a distinct pathway.
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Khang CH, Berruyer R, Giraldo MC, Kankanala P, Park SY, Czymmek K, Kang S, Valent B. Translocation of Magnaporthe oryzae effectors into rice cells and their subsequent cell-to-cell movement. Plant Cell 2010; 22:1388-403. [PMID: 20435900 PMCID: PMC2879738 DOI: 10.1105/tpc.109.069666] [Citation(s) in RCA: 294] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 03/11/2010] [Accepted: 04/14/2010] [Indexed: 05/17/2023]
Abstract
Knowledge remains limited about how fungal pathogens that colonize living plant cells translocate effector proteins inside host cells to regulate cellular processes and neutralize defense responses. To cause the globally important rice blast disease, specialized invasive hyphae (IH) invade successive living rice (Oryza sativa) cells while enclosed in host-derived extrainvasive hyphal membrane. Using live-cell imaging, we identified a highly localized structure, the biotrophic interfacial complex (BIC), which accumulates fluorescently labeled effectors secreted by IH. In each newly entered rice cell, effectors were first secreted into BICs at the tips of the initially filamentous hyphae in the cell. These tip BICs were left behind beside the first-differentiated bulbous IH cells as the fungus continued to colonize the host cell. Fluorescence recovery after photobleaching experiments showed that the effector protein PWL2 (for prevents pathogenicity toward weeping lovegrass [Eragrostis curvula]) continued to accumulate in BICs after IH were growing elsewhere. PWL2 and BAS1 (for biotrophy-associated secreted protein 1), BIC-localized secreted proteins, were translocated into the rice cytoplasm. By contrast, BAS4, which uniformly outlines the IH, was not translocated into the host cytoplasm. Fluorescent PWL2 and BAS1 proteins that reached the rice cytoplasm moved into uninvaded neighbors, presumably preparing host cells before invasion. We report robust assays for elucidating the molecular mechanisms that underpin effector secretion into BICs, translocation to the rice cytoplasm, and cell-to-cell movement in rice.
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Affiliation(s)
- Chang Hyun Khang
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas 66506
| | - Romain Berruyer
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas 66506
| | - Martha C. Giraldo
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas 66506
| | - Prasanna Kankanala
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas 66506
| | - Sook-Young Park
- Department of Plant Pathology, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Kirk Czymmek
- Department of Biological Sciences and Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19711
| | - Seogchan Kang
- Department of Plant Pathology, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Barbara Valent
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas 66506
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Pukkila-Worley R, Peleg AY, Tampakakis E, Mylonakis E. Candida albicans hyphal formation and virulence assessed using a Caenorhabditis elegans infection model. Eukaryot Cell 2009; 8:1750-8. [PMID: 19666778 PMCID: PMC2772404 DOI: 10.1128/ec.00163-09] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2009] [Accepted: 07/29/2009] [Indexed: 11/20/2022]
Abstract
Candida albicans colonizes the human gastrointestinal tract and can cause life-threatening systemic infection in susceptible hosts. We study here C. albicans virulence determinants using the nematode Caenorhabditis elegans in a pathogenesis system that models candidiasis. The yeast form of C. albicans is ingested into the C. elegans digestive tract. In liquid media, the yeast cells then undergo morphological change to form hyphae, which results in aggressive tissue destruction and death of the nematode. Several lines of evidence demonstrate that hyphal formation is critical for C. albicans pathogenesis in C. elegans. First, two yeast species unable to form hyphae (Debaryomyces hansenii and Candida lusitaniae) were less virulent than C. albicans in the C. elegans assay. Second, three C. albicans mutant strains compromised in their ability to form hyphae (efg1Delta/efg1Delta, flo8Delta/flo8Delta, and cph1Delta/cph1Delta efg1Delta/efg1Delta) were dramatically attenuated for virulence. Third, the conditional tet-NRG1 strain, which enables the external manipulation of morphogenesis in vivo, was more virulent toward C. elegans when the assay was conducted under conditions that permit hyphal growth. Finally, we demonstrate the utility of the C. elegans assay in a screen for C. albicans virulence determinants, which identified several genes important for both hyphal formation in vivo and the killing of C. elegans, including the recently described CAS5 and ADA2 genes. These studies in a C. elegans-C. albicans infection model provide insights into the virulence mechanisms of an important human pathogen.
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Affiliation(s)
- Read Pukkila-Worley
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts 02114, Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, Harvard Medical School, Boston, Massachusetts 02115
| | - Anton Y. Peleg
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts 02114, Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, Harvard Medical School, Boston, Massachusetts 02115
| | - Emmanouil Tampakakis
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts 02114, Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, Harvard Medical School, Boston, Massachusetts 02115
| | - Eleftherios Mylonakis
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts 02114, Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, Harvard Medical School, Boston, Massachusetts 02115
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Prats E, Carver TLW, Mur LAJ. Pathogen-derived nitric oxide influences formation of the appressorium infection structure in the phytopathogenic fungus Blumeria graminis. Res Microbiol 2008. [PMID: 18554873 DOI: 10.1016/j.resmic.2008.04.001>] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Nitric oxide (NO) is an important signal in plant resistance to pathogens. Here we report that NO is also generated by Blumeria graminis f.sp. hordei as a pathogenesis determinant on barley. Infection by B. graminis f.sp. hordei is dependent on appressorium formation in order to penetrate the host. Using fluorescent dye diaminofluorescein-2 diacetate (DAF-2DA) and confocal laser scanning microscopy, transient NO generation was detected within the B. graminis f.sp. hordei appressorium during its maturation. To confirm that NO was indeed being measured, DAF-2DA fluorescence was suppressed using a NO scavenger and a mammalian NO synthase inhibitor. Both chemicals affected the number of appressorial lobes produced by the fungus. These data indicate that NO plays a key role in formation of B. graminis f.sp. hordei appressoria.
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Affiliation(s)
- Elena Prats
- Institute of Sustainable Agriculture-CSIC, Alameda del Obispo, Menéndez Pidal s/n, 14080 Córdoba, Spain.
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Mitchell BM, Wu TG, Jackson BE, Wilhelmus KR. Candida albicansStrain-Dependent Virulence and Rim13p-Mediated Filamentation in Experimental Keratomycosis. ACTA ACUST UNITED AC 2007; 48:774-80. [PMID: 17251477 DOI: 10.1167/iovs.06-0793] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE To compare the virulence of wild-type Candida albicans strains in a murine model of corneal candidiasis and to investigate the role of fungal filamentation in disease progression. METHODS Scarified corneas of immunocompetent or cyclophosphamide-treated BALB/c mice were topically inoculated with one of three human isolates of C. albicans, a homozygous mutant of the pH-dependent filamentation gene rim13 or a mutant reference strain control. Mock-inoculated eyes served as negative controls. Corneal disease was categorized daily for 8 days with quantitative fungal culturing of eyes at 6 hours, 1 day, 4 days, and 8 days after infection and histopathologic examination at 1 day and 4 days after infection. RESULTS Corneal disease severity differed significantly among wild-type strains (P < or = 0.02). The rim13(-/-) mutant Tn7-rim13 was fully attenuated, whereas the mutant control DAY286 was fully virulent. Pretreatment of mice with cyclophosphamide increased susceptibility to wild-type C. albicans and partially rescued the attenuated phenotype of the genetically deficient rim13(-/-) fungal mutant. All strains replicated with similar kinetics in vitro, and wild-type strains had similar clearance from infected eyes. Histopathologic findings correlated with disease severity. CONCLUSIONS Wild-type strains of C. albicans that differ significantly in ocular pathogenicity correlate with the ability of yeast to produce pseudohyphae and hyphae and to invade corneal tissue. Full attenuation of the fungal rim13(-/-) mutant is the first direct demonstration of a hyphal morphogenesis-related gene as a specific virulence factor for C. albicans during corneal infection.
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Affiliation(s)
- Bradley M Mitchell
- Sid W. Richardson Ocular Microbiology Laboratory, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin, Houston, TX 77030, USA
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