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Kinase Hog1 and Adr1 Opposingly Regulate Haploid Cell Morphology by Controlling Vacuole Size in Sporisorium scitamineum. J Fungi (Basel) 2022; 8:jof8080865. [PMID: 36012854 PMCID: PMC9410113 DOI: 10.3390/jof8080865] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/13/2022] [Accepted: 08/15/2022] [Indexed: 11/16/2022] Open
Abstract
Morphogenesis is a strictly regulated efficient system in eukaryotes for adapting to environmental changes. However, the morphogenesis regulatory mechanism in smut fungi is not clear. This study reports a relationship between MAP kinase Hog1 and cAMP-dependent protein kinase A catalytic subunit (Adr1) for the morphological regulation in the sugarcane pathogen Sporisorium scitamineum. The results demonstrated that MAP kinase Hog1 and cAMP/PKA signaling pathways are essential for the morphological development of S. scitamineum. Interestingly, MAP kinase Hog1 and cAMP/PKA signaling pathways’ defective mutants exhibit an opposite morphological phenotype. The morphology of cAMP/PKA defective mutants is recovered by deleting the SsHOG1 gene. However, MAP kinase Hog1 and cAMP-dependent protein kinase catalytic subunit Adr1 do not interfere with each other. Further investigations showed that kinase Hog1 and Adr1 antagonistically regulates the vacuolar size, which contributes to the cell size and determines the cellular elongation rates. Kinase Hog1 and Adr1 also antagonistically balanced the cell wall integrity and permeability. Taken together, kinase Hog1- and Adr1-based opposing morphogenesis regulation of S. scitamineum by controlling the vacuolar size and cell wall permeability is established during the study.
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2
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Cai E, Sun S, Deng Y, Huang P, Sun X, Wang Y, Chang C, Jiang Z. Histidine Kinase Sln1 and cAMP/PKA Signaling Pathways Antagonistically Regulate Sporisorium scitamineum Mating and Virulence via Transcription Factor Prf1. J Fungi (Basel) 2021; 7:jof7080610. [PMID: 34436149 PMCID: PMC8397173 DOI: 10.3390/jof7080610] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/16/2021] [Accepted: 07/26/2021] [Indexed: 11/16/2022] Open
Abstract
Many prokaryotes and eukaryotes utilize two-component signaling pathways to counter environmental stress and regulate virulence genes associated with infection. In this study, we identified and characterized a conserved histidine kinase (SsSln1), which is the sensor of the two-component system of Sln1-Ypd1-Ssk1 in Sporisorium scitamineum. SsSln1 null mutant exhibited enhanced mating and virulence capabilities in S. scitamineum, which is opposite to what has been reported in Candida albicans. Further investigations revealed that the deletion of SsSLN1 enhanced SsHog1 phosphorylation and nuclear localization and thus promoted S. scitamineum mating. Interestingly, SsSln1 and cAMP/PKA signaling pathways antagonistically regulated the transcription of pheromone-responsive transcription factor SsPrf1, for regulating S. scitamineum mating and virulence. In short, the study depicts a novel mechanism in which the cross-talk between SsSln1 and cAMP/PKA pathways antagonistically regulates mating and virulence by balancing the transcription of the SsPRF1 gene in S. scitamineum.
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Affiliation(s)
- Enping Cai
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (E.C.); (S.S.); (Y.D.); (P.H.); (X.S.)
- Integrate Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China;
| | - Shuquan Sun
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (E.C.); (S.S.); (Y.D.); (P.H.); (X.S.)
- Environmental Monitoring and Remediation Engineering Technology Research Center, School of Environmental Engineering, Yellow River Conservancy Technical Institute, Kaifeng 475004, China
| | - Yizhen Deng
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (E.C.); (S.S.); (Y.D.); (P.H.); (X.S.)
- Integrate Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China;
| | - Peishen Huang
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (E.C.); (S.S.); (Y.D.); (P.H.); (X.S.)
- Integrate Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China;
| | - Xian Sun
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (E.C.); (S.S.); (Y.D.); (P.H.); (X.S.)
- Integrate Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China;
| | - Yuting Wang
- Integrate Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China;
| | - Changqing Chang
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (E.C.); (S.S.); (Y.D.); (P.H.); (X.S.)
- Integrate Microbiology Research Center, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China;
- Correspondence: (C.C.); (Z.J.); Tel.: +86-020-757-3225 (C.C.); +86-020-3860-4779 (Z.J.)
| | - Zide Jiang
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (E.C.); (S.S.); (Y.D.); (P.H.); (X.S.)
- Correspondence: (C.C.); (Z.J.); Tel.: +86-020-757-3225 (C.C.); +86-020-3860-4779 (Z.J.)
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3
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Kijpornyongpan T, Aime MC. Comparative transcriptomics reveal different mechanisms for hyphal growth across four plant-associated dimorphic fungi. Fungal Genet Biol 2021; 152:103565. [PMID: 33991665 DOI: 10.1016/j.fgb.2021.103565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 03/07/2021] [Accepted: 05/03/2021] [Indexed: 11/27/2022]
Abstract
Fungal dimorphism is a phenomenon by which a fungus can grow both as a yeast form and a hyphal form. It is frequently related to pathogenicity as different growth forms are more suitable for different functions during a life cycle. Among dimorphic plant pathogens, the corn smut fungus Ustilago maydis serves as a model organism to understand fungal dimorphism and its effect on pathogenicity. However, there is a lack of data on whether mechanisms elucidated from model species are broadly applicable to other fungi. In this study, two non-model plant-associated species in the smut fungus subphylum (Ustilaginomycotina), Tilletiopsis washingtonensis and Meira miltonrushii, were selected to compare dimorphic mechanisms in these to those in U. maydis. We sequenced transcriptomic profiles during both yeast and hyphal growth in these two species using Tween40, a lipid mimic, as a trigger for hyphal growth. We then compared our data with previously published data from U. maydis and a fourth but unrelated dimorphic phytopathogen, Ophiostoma novo-ulmi. Comparative transcriptomics was performed to identify common genes upregulated during hyphal growth in all four dimorphic species. Intriguingly, T. washingtonensis shares the least similarities of transcriptomic alteration (hyphal growth versus yeast growth) with the others, although it is closely related to M. miltonrushii and U. maydis. This suggests that phylogenetic relatedness is not correlated with transcriptomic similarity under the same biological phenomenon. Among commonly expressed genes in the four species, genes in cell energy production and conversion, amino acid transport and metabolism and cytoskeleton are significantly enriched. Considering dimorphism genes characterized in U. maydis, as well as hyphal tip-associated genes from the literature, we found only genes encoding the cell end marker Tea4/TeaC and the kinesin motor protein Kin3 concordantly expressed in all four species. This suggests a divergence in species-specific mechanisms for dimorphic transition and hyphal growth.
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Affiliation(s)
- Teeratas Kijpornyongpan
- Department of Botany and Plant Pathology, Purdue University, 915 W State St, West Lafayette, IN 47907-2054, USA
| | - M Catherine Aime
- Department of Botany and Plant Pathology, Purdue University, 915 W State St, West Lafayette, IN 47907-2054, USA.
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Kijpornyongpan T, Aime MC. Investigating the Smuts: Common Cues, Signaling Pathways, and the Role of MAT in Dimorphic Switching and Pathogenesis. J Fungi (Basel) 2020; 6:jof6040368. [PMID: 33339287 PMCID: PMC7766764 DOI: 10.3390/jof6040368] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/10/2020] [Accepted: 12/14/2020] [Indexed: 12/11/2022] Open
Abstract
The corn smut fungus Ustilago maydis serves as a model species for studying fungal dimorphism and its role in phytopathogenic development. The pathogen has two growth phases: a saprobic yeast phase and a pathogenic filamentous phase. Dimorphic transition of U. maydis involves complex processes of signal perception, mating, and cellular reprogramming. Recent advances in improvement of reference genomes, high-throughput sequencing and molecular genetics studies have been expanding research in this field. However, the biology of other non-model species is frequently overlooked. This leads to uncertainty regarding how much of what is known in U. maydis is applicable to other dimorphic fungi. In this review, we will discuss dimorphic fungi in the aspects of physiology, reproductive biology, genomics, and molecular genetics. We also perform comparative analyses between U. maydis and other fungi in Ustilaginomycotina, the subphylum to which U. maydis belongs. We find that lipid/hydrophobicity is a potential common cue for dimorphic transition in plant-associated dimorphic fungi. However, genomic profiles alone are not adequate to explain dimorphism across different fungi.
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Martínez-Soto D, Ortiz-Castellanos L, Robledo-Briones M, León-Ramírez CG. Molecular Mechanisms Involved in the Multicellular Growth of Ustilaginomycetes. Microorganisms 2020; 8:E1072. [PMID: 32708448 PMCID: PMC7409079 DOI: 10.3390/microorganisms8071072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/12/2020] [Accepted: 07/16/2020] [Indexed: 12/23/2022] Open
Abstract
Multicellularity is defined as the developmental process by which unicellular organisms became pluricellular during the evolution of complex organisms on Earth. This process requires the convergence of genetic, ecological, and environmental factors. In fungi, mycelial and pseudomycelium growth, snowflake phenotype (where daughter cells remain attached to their stem cells after mitosis), and fruiting bodies have been described as models of multicellular structures. Ustilaginomycetes are Basidiomycota fungi, many of which are pathogens of economically important plant species. These fungi usually grow unicellularly as yeasts (sporidia), but also as simple multicellular forms, such as pseudomycelium, multicellular clusters, or mycelium during plant infection and under different environmental conditions: Nitrogen starvation, nutrient starvation, acid culture media, or with fatty acids as a carbon source. Even under specific conditions, Ustilago maydis can form basidiocarps or fruiting bodies that are complex multicellular structures. These fungi conserve an important set of genes and molecular mechanisms involved in their multicellular growth. In this review, we will discuss in-depth the signaling pathways, epigenetic regulation, required polyamines, cell wall synthesis/degradation, polarized cell growth, and other cellular-genetic processes involved in the different types of Ustilaginomycetes multicellular growth. Finally, considering their short life cycle, easy handling in the laboratory and great morphological plasticity, Ustilaginomycetes can be considered as model organisms for studying fungal multicellularity.
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Affiliation(s)
- Domingo Martínez-Soto
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, USA
- Tecnológico Nacional de México, Instituto Tecnológico Superior de Los Reyes, Los Reyes 60300, Mexico
| | - Lucila Ortiz-Castellanos
- Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato 36821, Mexico; (L.O.-C.); (C.G.L.-R.)
| | - Mariana Robledo-Briones
- Departamento de Microbiología y Genética, Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Universidad de Salamanca, 37185 Salamanca, Spain;
| | - Claudia Geraldine León-Ramírez
- Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato 36821, Mexico; (L.O.-C.); (C.G.L.-R.)
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6
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Liu KH, Shen WC. Sexual Differentiation Is Coordinately Regulated by Cryptococcus neoformans CRK1 and GAT1. Genes (Basel) 2020; 11:genes11060669. [PMID: 32575488 PMCID: PMC7349709 DOI: 10.3390/genes11060669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 06/05/2020] [Accepted: 06/16/2020] [Indexed: 12/02/2022] Open
Abstract
The heterothallic basidiomycetous fungus Cryptococcus neoformans has two mating types, MATa and MATα. Morphological progression of bisexual reproduction in C. neoformans is as follows: yeast to hyphal transition, filament extension, basidium formation, meiosis, and sporulation. C. neoformans Cdk-related kinase 1 (CRK1) is a negative regulator of bisexual mating. In this study, we characterized the morphological features of mating structures in the crk1 mutant and determined the genetic interaction of CRK1 in the regulatory networks of sexual differentiation. In the bilateral crk1 mutant cross, despite shorter length of filaments than in the wild-type cross, dikaryotic filaments and other structures still remained intact during bisexual mating, but the timing of basidium formation was approximately 18 h earlier than in the cross between wild type strains. Furthermore, gene expression analyses revealed that CRK1 modulated the expression of genes involved in the progression of hyphal elongation, basidium formation, karyogamy and meiosis. Phenotypic results showed that, although deletion of C. neoformans CRK1 gene increased the efficiency of bisexual mating, filamentation in the crk1 mutant was blocked by MAT2 or ZNF2 mutation. A bioinformatics survey predicted the C. neoformans GATA transcriptional factor Gat1 as a potential substrate of Crk1 kinase. Our genetic and phenotypic findings revealed that C. neoformansGAT1 and CRK1 formed a regulatory circuit to negatively regulate MAT2 to control filamentation progression and transition during bisexual mating.
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Xie M, Bai N, Yang J, Jiang K, Zhou D, Zhao Y, Li D, Niu X, Zhang KQ, Yang J. Protein Kinase Ime2 Is Required for Mycelial Growth, Conidiation, Osmoregulation, and Pathogenicity in Nematode-Trapping Fungus Arthrobotrys oligospora. Front Microbiol 2020; 10:3065. [PMID: 31993040 PMCID: PMC6971104 DOI: 10.3389/fmicb.2019.03065] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 12/18/2019] [Indexed: 11/26/2022] Open
Abstract
Inducer of meiosis 2 (Ime2), a protein kinase that has been identified in diverse fungal species, functions in the regulation of various cellular processes, such as ascospore formation, pseudohyphal growth, and sexual reproduction. In this study, AoIme2, an ortholog of Saccharomyces cerevisiae Ime2, was characterized in the nematode-trapping fungus Arthrobotrys oligospora. Disruption of the gene Aoime2 caused defective growth, with slower mycelial growth in ΔAoime2 mutants than the wild type (WT) strain, and in the mutants, the number of hyphal septa in mycelia was higher and the number of cell nuclei in mycelia and conidia was considerably lower than in the WT strain. The conidial yields of the ΔAoime2 mutants were decreased by ∼33% relative to the WT strain, and the transcription of several sporulation-related genes, including abaA, fluG, rodA, aspB, velB, and vosA, was markedly downregulated during the conidiation stage. The ΔAoime2 mutants were highly sensitive to the osmotic stressors NaCl and sorbitol, and the cell wall of partial hyphae in the mutants was deformed. Further examination revealed that the cell wall of the traps produced by ΔAoime2 mutants became loose, and that the electron-dense bodies in trap cells were also few than in the WT strain. Moreover, Aoime2 disruption caused a reduction in trap formation and serine-protease production, and most hyphal traps produced by ΔAoime2 mutants did not form an intact hyphal loop; consequently, substantially fewer nematodes were captured by the mutants than by the WT strain. In summary, an Ime2-MAPK is identified here for the first time from a nematode-trapping fungus, and the kinase is shown to be involved in the regulation of mycelial growth and development, conidiation, osmolarity, and pathogenicity in A. oligospora.
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Affiliation(s)
- Meihua Xie
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China.,Department of Chemistry and Life Science, Chuxiong Normal University, Chuxiong, China
| | - Na Bai
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Jiangliu Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Kexin Jiang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Duanxu Zhou
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Yining Zhao
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Dongni Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Xuemei Niu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Ke-Qin Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Jinkui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
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8
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Bardetti P, Castanheira SM, Valerius O, Braus GH, Pérez-Martín J. Cytoplasmic retention and degradation of a mitotic inducer enable plant infection by a pathogenic fungus. eLife 2019; 8:e48943. [PMID: 31621584 PMCID: PMC6887120 DOI: 10.7554/elife.48943] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 10/16/2019] [Indexed: 11/13/2022] Open
Abstract
In the fungus Ustilago maydis, sexual pheromones elicit mating resulting in an infective filament able to infect corn plants. Along this process a G2 cell cycle arrest is mandatory. Such as cell cycle arrest is initiated upon the pheromone recognition in each mating partner, and sustained once cell fusion occurred until the fungus enter the plant tissue. We describe that the initial cell cycle arrest resulted from inhibition of the nuclear transport of the mitotic inducer Cdc25 by targeting its importin, Kap123. Near cell fusion to take place, the increase on pheromone signaling promotes Cdc25 degradation, which seems to be important to ensure the maintenance of the G2 cell cycle arrest to lead the formation of the infective filament. This way, premating cell cycle arrest is linked to the subsequent steps required for establishment of the infection. Disabling this connection resulted in the inability of fungal cells to infect plants.
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Affiliation(s)
- Paola Bardetti
- Instituto de Biología Funcional y Genómica (CSIC)SalamancaSpain
| | | | - Oliver Valerius
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and GeneticsGeorg-August-UniversityGöttingenGermany
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and GeneticsGeorg-August-UniversityGöttingenGermany
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9
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Etxebeste O, Espeso EA. Neurons show the path: tip-to-nucleus communication in filamentous fungal development and pathogenesis. FEMS Microbiol Rev 2017; 40:610-24. [PMID: 27587717 DOI: 10.1093/femsre/fuw021] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2016] [Indexed: 01/11/2023] Open
Abstract
Multiple fungal species penetrate substrates and accomplish host invasion through the fast, permanent and unidirectional extension of filamentous cells known as hyphae. Polar growth of hyphae results, however, in a significant increase in the distance between the polarity site, which also receives the earliest information about ambient conditions, and nuclei, where adaptive responses are executed. Recent studies demonstrate that these long distances are overcome by signal transduction pathways which convey sensory information from the polarity site to nuclei, controlling development and pathogenesis. The present review compares the striking connections of the mechanisms for long-distance communication in hyphae with those from neurons, and discusses the importance of their study in order to understand invasion and dissemination processes of filamentous fungi, and design strategies for developmental control in the future.
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Affiliation(s)
- Oier Etxebeste
- Biochemistry II laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country (UPV/EHU), 20018 San Sebastian, Spain
| | - Eduardo A Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
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10
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Abstract
Filamentous fungi are a large and ancient clade of microorganisms that occupy a broad range of ecological niches. The success of filamentous fungi is largely due to their elongate hypha, a chain of cells, separated from each other by septa. Hyphae grow by polarized exocytosis at the apex, which allows the fungus to overcome long distances and invade many substrates, including soils and host tissues. Hyphal tip growth is initiated by establishment of a growth site and the subsequent maintenance of the growth axis, with transport of growth supplies, including membranes and proteins, delivered by motors along the cytoskeleton to the hyphal apex. Among the enzymes delivered are cell wall synthases that are exocytosed for local synthesis of the extracellular cell wall. Exocytosis is opposed by endocytic uptake of soluble and membrane-bound material into the cell. The first intracellular compartment in the endocytic pathway is the early endosomes, which emerge to perform essential additional functions as spatial organizers of the hyphal cell. Individual compartments within septated hyphae can communicate with each other via septal pores, which allow passage of cytoplasm or organelles to help differentiation within the mycelium. This article introduces the reader to more detailed aspects of hyphal growth in fungi.
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11
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Schmoll M, Dattenböck C, Carreras-Villaseñor N, Mendoza-Mendoza A, Tisch D, Alemán MI, Baker SE, Brown C, Cervantes-Badillo MG, Cetz-Chel J, Cristobal-Mondragon GR, Delaye L, Esquivel-Naranjo EU, Frischmann A, Gallardo-Negrete JDJ, García-Esquivel M, Gomez-Rodriguez EY, Greenwood DR, Hernández-Oñate M, Kruszewska JS, Lawry R, Mora-Montes HM, Muñoz-Centeno T, Nieto-Jacobo MF, Nogueira Lopez G, Olmedo-Monfil V, Osorio-Concepcion M, Piłsyk S, Pomraning KR, Rodriguez-Iglesias A, Rosales-Saavedra MT, Sánchez-Arreguín JA, Seidl-Seiboth V, Stewart A, Uresti-Rivera EE, Wang CL, Wang TF, Zeilinger S, Casas-Flores S, Herrera-Estrella A. The Genomes of Three Uneven Siblings: Footprints of the Lifestyles of Three Trichoderma Species. Microbiol Mol Biol Rev 2016; 80:205-327. [PMID: 26864432 PMCID: PMC4771370 DOI: 10.1128/mmbr.00040-15] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The genus Trichoderma contains fungi with high relevance for humans, with applications in enzyme production for plant cell wall degradation and use in biocontrol. Here, we provide a broad, comprehensive overview of the genomic content of these species for "hot topic" research aspects, including CAZymes, transport, transcription factors, and development, along with a detailed analysis and annotation of less-studied topics, such as signal transduction, genome integrity, chromatin, photobiology, or lipid, sulfur, and nitrogen metabolism in T. reesei, T. atroviride, and T. virens, and we open up new perspectives to those topics discussed previously. In total, we covered more than 2,000 of the predicted 9,000 to 11,000 genes of each Trichoderma species discussed, which is >20% of the respective gene content. Additionally, we considered available transcriptome data for the annotated genes. Highlights of our analyses include overall carbohydrate cleavage preferences due to the different genomic contents and regulation of the respective genes. We found light regulation of many sulfur metabolic genes. Additionally, a new Golgi 1,2-mannosidase likely involved in N-linked glycosylation was detected, as were indications for the ability of Trichoderma spp. to generate hybrid galactose-containing N-linked glycans. The genomic inventory of effector proteins revealed numerous compounds unique to Trichoderma, and these warrant further investigation. We found interesting expansions in the Trichoderma genus in several signaling pathways, such as G-protein-coupled receptors, RAS GTPases, and casein kinases. A particularly interesting feature absolutely unique to T. atroviride is the duplication of the alternative sulfur amino acid synthesis pathway.
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Affiliation(s)
- Monika Schmoll
- Austrian Institute of Technology, Department Health and Environment, Bioresources Unit, Tulln, Austria
| | - Christoph Dattenböck
- Austrian Institute of Technology, Department Health and Environment, Bioresources Unit, Tulln, Austria
| | | | | | - Doris Tisch
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | - Mario Ivan Alemán
- Cinvestav, Department of Genetic Engineering, Irapuato, Guanajuato, Mexico
| | - Scott E Baker
- Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Christopher Brown
- University of Otago, Department of Biochemistry and Genetics, Dunedin, New Zealand
| | | | - José Cetz-Chel
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
| | | | - Luis Delaye
- Cinvestav, Department of Genetic Engineering, Irapuato, Guanajuato, Mexico
| | | | - Alexa Frischmann
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | | | - Monica García-Esquivel
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
| | | | - David R Greenwood
- The University of Auckland, School of Biological Sciences, Auckland, New Zealand
| | - Miguel Hernández-Oñate
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
| | - Joanna S Kruszewska
- Polish Academy of Sciences, Institute of Biochemistry and Biophysics, Laboratory of Fungal Glycobiology, Warsaw, Poland
| | - Robert Lawry
- Lincoln University, Bio-Protection Research Centre, Lincoln, Canterbury, New Zealand
| | | | | | | | | | | | | | - Sebastian Piłsyk
- Polish Academy of Sciences, Institute of Biochemistry and Biophysics, Laboratory of Fungal Glycobiology, Warsaw, Poland
| | - Kyle R Pomraning
- Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Aroa Rodriguez-Iglesias
- Austrian Institute of Technology, Department Health and Environment, Bioresources Unit, Tulln, Austria
| | | | | | - Verena Seidl-Seiboth
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | | | | | - Chih-Li Wang
- National Chung-Hsing University, Department of Plant Pathology, Taichung, Taiwan
| | - Ting-Fang Wang
- Academia Sinica, Institute of Molecular Biology, Taipei, Taiwan
| | - Susanne Zeilinger
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria University of Innsbruck, Institute of Microbiology, Innsbruck, Austria
| | | | - Alfredo Herrera-Estrella
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
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12
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Chen F, Chen XZ, Su XY, Qin LN, Huang ZB, Tao Y, Dong ZY. An Ime2-like mitogen-activated protein kinase is involved in cellulase expression in the filamentous fungus Trichoderma reesei. Biotechnol Lett 2015; 37:2055-62. [DOI: 10.1007/s10529-015-1888-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/10/2015] [Indexed: 11/28/2022]
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13
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Castanheira S, Mielnichuk N, Pérez-Martín J. Programmed cell cycle arrest is required for infection of corn plants by the fungus Ustilago maydis. Development 2014; 141:4817-26. [PMID: 25411209 DOI: 10.1242/dev.113415] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ustilago maydis is a plant pathogen that requires a specific structure called infective filament to penetrate the plant tissue. Although able to grow, this filament is cell cycle arrested on the plant surface. This cell cycle arrest is released once the filament penetrates the plant tissue. The reasons and mechanisms for this cell cycle arrest are unknown. Here, we have tried to address these questions. We reached three conclusions from our studies. First, the observed cell cycle arrest is the result of the cooperation of at least two distinct mechanisms: one involving the activation of the DNA damage response (DDR) cascade; and the other relying on the transcriptional downregulation of Hsl1, a kinase that modulates the G2/M transition. Second, a sustained cell cycle arrest during the infective filament step is necessary for the virulence in U. maydis, as a strain unable to arrest the cell cycle was severely impaired in its ability to infect corn plants. Third, production of the appressorium, a structure required for plant penetration, is incompatible with an active cell cycle. The inability to infect plants by strains defective in cell cycle arrest seems to be caused by their failure to induce the appressorium formation process. In summary, our findings uncover genetic circuits to arrest the cell cycle during the growth of this fungus on the plant surface, thus allowing the penetration into plant tissue.
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Affiliation(s)
- Sónia Castanheira
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Zacarías González 2, Salamanca 37007, Spain
| | - Natalia Mielnichuk
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Zacarías González 2, Salamanca 37007, Spain
| | - José Pérez-Martín
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Zacarías González 2, Salamanca 37007, Spain
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14
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Long-distance endosome trafficking drives fungal effector production during plant infection. Nat Commun 2014; 5:5097. [PMID: 25283249 PMCID: PMC4205857 DOI: 10.1038/ncomms6097] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 08/28/2014] [Indexed: 01/29/2023] Open
Abstract
To cause plant disease, pathogenic fungi can secrete effector proteins into plant cells to suppress plant immunity and facilitate fungal infection. Most fungal pathogens infect plants using very long strand-like cells, called hyphae, that secrete effectors from their tips into host tissue. How fungi undergo long-distance cell signalling to regulate effector production during infection is not known. Here we show that long-distance retrograde motility of early endosomes (EEs) is necessary to trigger transcription of effector-encoding genes during plant infection by the pathogenic fungus Ustilago maydis. We demonstrate that motor-dependent retrograde EE motility is necessary for regulation of effector production and secretion during host cell invasion. We further show that retrograde signalling involves the mitogen-activated kinase Crk1 that travels on EEs and participates in control of effector production. Fungal pathogens therefore undergo long-range signalling to orchestrate host invasion. It is unclear how the nuclei of very long fungal cells (hyphae) receive information from the hyphal tips during the invasion of plant tissues. Here, the authors show that retrograde movement of early endosomes, from the hyphal tip to the nucleus, is required for this signalling process.
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15
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The SPF27 homologue Num1 connects splicing and kinesin 1-dependent cytoplasmic trafficking in Ustilago maydis. PLoS Genet 2014; 10:e1004046. [PMID: 24391515 PMCID: PMC3879195 DOI: 10.1371/journal.pgen.1004046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 10/30/2013] [Indexed: 12/23/2022] Open
Abstract
The conserved NineTeen protein complex (NTC) is an integral subunit of the spliceosome and required for intron removal during pre-mRNA splicing. The complex associates with the spliceosome and participates in the regulation of conformational changes of core spliceosomal components, stabilizing RNA-RNA- as well as RNA-protein interactions. In addition, the NTC is involved in cell cycle checkpoint control, response to DNA damage, as well as formation and export of mRNP-particles. We have identified the Num1 protein as the homologue of SPF27, one of NTC core components, in the basidiomycetous fungus Ustilago maydis. Num1 is required for polarized growth of the fungal hyphae, and, in line with the described NTC functions, the num1 mutation affects the cell cycle and cell division. The num1 deletion influences splicing in U. maydis on a global scale, as RNA-Seq analysis revealed increased intron retention rates. Surprisingly, we identified in a screen for Num1 interacting proteins not only NTC core components as Prp19 and Cef1, but several proteins with putative functions during vesicle-mediated transport processes. Among others, Num1 interacts with the motor protein Kin1 in the cytoplasm. Similar phenotypes with respect to filamentous and polar growth, vacuolar morphology, as well as the motility of early endosomes corroborate the genetic interaction between Num1 and Kin1. Our data implicate a previously unidentified connection between a component of the splicing machinery and cytoplasmic transport processes. As the num1 deletion also affects cytoplasmic mRNA transport, the protein may constitute a novel functional interconnection between the two disparate processes of splicing and trafficking. In eukaryotic cells, nascent mRNA is processed by splicing to remove introns and to join the exon sequences. The processed mRNA is then transported out of the nucleus and employed by ribosomes to synthesize proteins. Splicing is achieved by the spliceosome and associated protein complexes, among them the so-called NineTeen complex (NTC). We have identified the Num1 protein as one of the core components of the NTC in the fungus Ustilago maydis, and could show that it is required for polarized growth of the filamentous fungal cells. Consistent with the NTC function, cells with a num1-deletion show reduced splicing of mRNA. Moreover, we uncover a novel cytoplasmic function of the Num1 protein: It physically interacts with the microtubule-associated Kinesin 1 motor protein, and phenotypic analyses corroborate that both proteins are functionally connected. Our findings reveal a yet unidentified role of a global splicing factor during intracellular trafficking processes. A possible connection between these disparate mechanisms presumably resides in mRNA-export out of the nucleus and/or the transport of mRNA within the cytoplasm.
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16
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Abstract
A central feature of meiosis is the pairing and recombination of homologous chromosomes. Ustilago maydis, a biotrophic fungus that parasitizes maize, has long been utilized as an experimental system for studying recombination, but it has not been clear when in the life cycle meiotic recombination initiates. U. maydis forms dormant diploid teliospores as the end product of the infection process. Upon germination, teliospores complete meiosis to produce four haploid basidiospores. Here we asked whether the meiotic process begins when teliospores germinate or at an earlier stage in development. When teliospores homozygous for a cdc45 mutation temperature sensitive for DNA synthesis were germinated at the restrictive temperature, four nuclei became visible. This implies that teliospores have already undergone premeiotic DNA synthesis and suggests that meiotic recombination initiates at a stage of infection before teliospores mature. Determination of homologous recombination in plant tissue infected with U. maydis strains heteroallelic for the nar1 gene revealed that Nar(+) recombinants were produced at a stage before teliospore maturation. Teliospores obtained from a spo11Δ cross were still able to germinate but the process was highly disturbed and the meiotic products were imbalanced in chromosomal complement. These results show that in U. maydis, homologous recombination initiates during the infection process and that meiosis can proceed even in the absence of Spo11, but with loss of genomic integrity.
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17
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Sartorel E, Pérez-Martín J. The distinct interaction between cell cycle regulation and the widely conserved morphogenesis-related (MOR) pathway in the fungus Ustilago maydis determines morphology. J Cell Sci 2012; 125:4597-608. [PMID: 22767510 DOI: 10.1242/jcs.107862] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The morphogenesis-related NDR kinase (MOR) pathway regulates morphogenesis in fungi. In spite of the high conservation of its components, impairing their functions results in highly divergent cellular responses depending on the fungal species. The reasons for such differences are unclear. Here we propose that the species-specific connections between cell cycle regulation and the MOR pathway could be partly responsible for these divergences. We based our conclusion on the characterization of the MOR pathway in the fungus Ustilago maydis. Each gene that encodes proteins of this pathway in U. maydis was deleted. All mutants exhibited a constitutive hyperpolarized growth, contrasting with the loss of polarity observed in other fungi. Using a conditional allele of the central NDR kinase Ukc1, we found that impairing MOR function resulted in a prolonged G2 phase. This cell cycle delay appears to be the consequence of an increase in Cdk1 inhibitory phosphorylation. Strikingly, prevention of the inhibitory Cdk1 phosphorylation abolished the hyperpolarized growth associated with MOR pathway depletion. We found that the prolonged G2 phase resulted in higher levels of expression of crk1, a conserved kinase that promotes polar growth in U. maydis. Deletion of crk1 also abolished the dramatic activation of polar growth in cells lacking the MOR pathway. Taken together, our results suggest that Cdk1 inhibitory phosphorylation may act as an integrator of signaling cascades regulating fungal morphogenesis and that the distinct morphological response observed in U. maydis upon impairment of the MOR pathway could be due to a cell cycle deregulation.
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Affiliation(s)
- Elodie Sartorel
- Instituto de Biología Funcional y Genómica (CSIC), 37007 Salamanca, Spain
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18
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Wang L, Berndt P, Xia X, Kahnt J, Kahmann R. A seven-WD40 protein related to human RACK1 regulates mating and virulence in Ustilago maydis. Mol Microbiol 2011; 81:1484-98. [PMID: 21815950 DOI: 10.1111/j.1365-2958.2011.07783.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In mammalian cells RACK1 serves as a scaffold protein that has a role in integrating inputs from different signalling pathways and affects translation through association with ribosomes. Ustilago maydis contains a seven-WD40 repeat motif protein designated Rak1, which shows 68% identity to RACK1 and 51% identity to Asc1p of Saccharomyces cerevisiae. An asc1 mutant could be complemented by introduction of U. maydis rak1. The deletion of rak1 affected cell growth, cell wall integrity and specifically attenuated cell fusion. This latter defect was caused by reduced expression of prf1 encoding the regulator for pheromone (mfa) and pheromone-receptor genes. Rak1 interacts with a variety of ribosomal proteins and microarray analysis revealed that the deletion of rak1 led to severely reduced expression of rop1, a transcriptional activator of prf1. The constitutive expression of rop1 could rescue the defect of mfa1 expression as well as conjugation tube formation in response to pheromone induction in the rak1 mutant. Moreover, a solopathogenic rak1 mutant failed to respond to plant-derived stimuli, resulting in attenuated filamentation and pathogenicity. This could be partially rescued by constitutive expression of the b heterodimer. These data suggest that rak1 is a regulator of rop1 expression with additional roles after cell fusion.
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Affiliation(s)
- Lei Wang
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, D-35043 Marburg, Germany
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19
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Bayram O, Braus GH. Coordination of secondary metabolism and development in fungi: the velvet family of regulatory proteins. FEMS Microbiol Rev 2011; 36:1-24. [PMID: 21658084 DOI: 10.1111/j.1574-6976.2011.00285.x] [Citation(s) in RCA: 388] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Filamentous fungi produce a number of small bioactive molecules as part of their secondary metabolism ranging from benign antibiotics such as penicillin to threatening mycotoxins such as aflatoxin. Secondary metabolism can be linked to fungal developmental programs in response to various abiotic or biotic external triggers. The velvet family of regulatory proteins plays a key role in coordinating secondary metabolism and differentiation processes such as asexual or sexual sporulation and sclerotia or fruiting body formation. The velvet family shares a protein domain that is present in most parts of the fungal kingdom from chytrids to basidiomycetes. Most of the current knowledge derives from the model Aspergillus nidulans where VeA, the founding member of the protein family, was discovered almost half a century ago. Different members of the velvet protein family interact with each other and the nonvelvet protein LaeA, primarily in the nucleus. LaeA is a methyltransferase-domain protein that functions as a regulator of secondary metabolism and development. A comprehensive picture of the molecular interplay between the velvet domain protein family, LaeA and other nuclear regulatory proteins in response to various signal transduction pathway starts to emerge from a jigsaw puzzle of several recent studies.
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Affiliation(s)
- Ozgür Bayram
- Institut für Mikrobiologie und Genetik, Abteilung Molekulare Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Göttingen, Germany
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20
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The F-Box protein Fbp1 regulates sexual reproduction and virulence in Cryptococcus neoformans. EUKARYOTIC CELL 2011; 10:791-802. [PMID: 21478432 DOI: 10.1128/ec.00004-11] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cryptococcus neoformans is the leading cause of fungal meningitis in immunocomprised populations. Although extensive studies have been conducted on signal transduction pathways important for fungal sexual reproduction and virulence, how fungal virulence is regulated during infection is still not understood. In this study, we identified the F-box protein Fbp1, which contains a putative F-box domain and 12 leucine-rich repeats (LRR). Although fbp1 mutants showed normal growth and produced normal major virulence factors, such as melanin and capsule, Fbp1 was found to be essential for fungal virulence, as fbp1 mutants were avirulent in a murine systemic-infection model. Fbp1 is also important for fungal sexual reproduction. Basidiospore production was blocked in bilateral mating between fbp1 mutants, even though normal dikaryotic hyphae were observed during mating. In vitro assays of stress responses revealed that fbp1 mutants are hypersensitive to SDS, but not calcofluor white (CFW) or Congo red, indicating that Fbp1 may regulate cell membrane integrity. Fbp1 physically interacts with Skp1 homologues in both Saccharomyces cerevisiae and C. neoformans via its F-box domain, suggesting it may function as part of an SCF (Skp1, Cullins, F-box proteins) E3 ligase. Overall, our study revealed that the F-box protein Fbp1 is essential for fungal sporulation and virulence in C. neoformans, which likely represents a conserved novel virulence control mechanism that involves the SCF E3 ubiquitin ligase-mediated proteolysis pathway.
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21
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Abstract
Ime2 of the budding yeast Saccharomyces cerevisiae belongs to a family of conserved protein kinases displaying sequence similarities to both cyclin-dependent kinases and mitogen-activated protein kinases. Ime2 has a pivotal role for meiosis and sporulation. The involvement of this protein kinase in the regulation of various key events in meiosis, such as the initiation of DNA replication, the expression of meiosis-specific genes and the passage through the two consecutive rounds of nuclear divisions has been characterized in detail. More than 20 years after the identification of the IME2 gene, a recent report has provided the first evidence for a function of this gene outside of meiosis, which is the regulation of pseudohyphal growth. In the last few years, Ime2-related protein kinases from various fungal species were studied. Remarkably, these homologues are not generally required for meiosis, but instead have other specific tasks. In filamentous ascomycete species, Ime2 homologues are involved in the inhibition of fruiting body formation in response to environmental signals. In the pathogenic basidiomycetes Ustilago maydis and Cryptococcus neoformans, members of this kinase family apparently have primary roles in regulating mating. Thus, Ime2-related kinases exhibit an amazing variety in controlling sexual developmental programs in fungi.
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Affiliation(s)
- Stefan Irniger
- Institute of Microbiology and Genetics, Georg August University, Grisebachstr. 8, D-37077 Göttingen, Germany.
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22
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Liu KH, Shen WC. Mating differentiation in Cryptococcus neoformans is negatively regulated by the Crk1 protein kinase. Fungal Genet Biol 2010; 48:225-40. [PMID: 21111055 DOI: 10.1016/j.fgb.2010.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Revised: 11/12/2010] [Accepted: 11/13/2010] [Indexed: 01/27/2023]
Abstract
Cryptococcus neoformans is a heterothallic basidiomycete that grows vegetatively as yeast and filamentous hyphae are produced in the sexual state. Previous studies have shown that C. neoformans Cwc1 and Cwc2 are two central photoregulators which form a complex to inhibit the production of sexual filaments upon light treatment. To reveal the detailed regulatory mechanisms, a genome wide mutagenesis screen was conducted and components in the Cwc1/Cwc2 complex mediated pathway have been identified. In this study, one suppressor mutant, DJ22, is characterized and T-DNA is found to disrupt the C. neoformans CRK1 gene, a homologue of Saccharomyces cerevisiae IME2 and Ustilago maydis crk1. Ime2 is a meiosis-specific gene with the conserved Ser/Thr kinase domain and TXY dual phosphorylation site. Consistent with the findings of other suppressors in our screen, C. neoformans Crk1 plays a negative role in the mating process. Dikaryotic filaments, basidia, and basidiospores are produced earlier in the crk1 mutant crosses and mating efficiency is also increased. Artificial elevation of the CRK1 mRNA level inhibits mating. Interestingly, monokaryotic fruiting is defective both in the MATα crk1 mutant and CRK1 overexpression strains. Our studies demonstrate that C. neoformans CRK1 gene functions as a negative regulator in the mating differentiation.
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Affiliation(s)
- Kuang-Hung Liu
- Department of Plant Pathology and Microbiology, National Taiwan University, No. 1 Roosevelt Road, Taipei, Taiwan
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23
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Ime1 and Ime2 are required for pseudohyphal growth of Saccharomyces cerevisiae on nonfermentable carbon sources. Mol Cell Biol 2010; 30:5514-30. [PMID: 20876298 DOI: 10.1128/mcb.00390-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudohyphal growth and meiosis are two differentiation responses to nitrogen starvation of diploid Saccharomyces cerevisiae. Nitrogen starvation in the presence of fermentable carbon sources is thought to induce pseudohyphal growth, whereas nitrogen and sugar starvation induces meiosis. In contrast to the genetic background routinely used to study pseudohyphal growth (Σ1278b), nonfermentable carbon sources stimulate pseudohyphal growth in the efficiently sporulating strain SK1. Pseudohyphal SK1 cells can exit pseudohyphal growth to complete meiosis. Two stimulators of meiosis, Ime1 and Ime2, are required for pseudohyphal growth of SK1 cells in the presence of nonfermentable carbon sources. Epistasis analysis suggests that Ime1 and Ime2 act in the same order in pseudohyphal growth as in meiosis. The different behaviors of strains SK1 and Σ1278b are in part attributable to differences in cyclic AMP (cAMP) signaling. In contrast to Σ1278b cells, hyperactivation of cAMP signaling using constitutively active Ras2(G19V) inhibited pseudohyphal growth in SK1 cells. Our data identify the SK1 genetic background as an alternative genetic background for the study of pseudohyphal growth and suggest an overlap between signaling pathways controlling pseudohyphal growth and meiosis. Based on these findings, we propose to include exit from pseudohyphal growth and entry into meiosis in the life cycle of S. cerevisiae.
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24
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Di Stasio M, Brefort T, Mendoza-Mendoza A, Münch K, Kahmann R. The dual specificity phosphatase Rok1 negatively regulates mating and pathogenicity in Ustilago maydis. Mol Microbiol 2009; 73:73-88. [PMID: 19486294 DOI: 10.1111/j.1365-2958.2009.06747.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In the phytopathogenic fungus Ustilago maydis a conserved mitogen-activated-protein-kinase (MAPK) module regulates sexual and pathogenic development. Kpp2 is the central MAPK of this module and is required for transcriptional and morphological responses to pheromone. Upon perception of the pheromone signal Kpp2 is phosphorylated by the MAPK kinase Fuz7. Here we demonstrate that the MAPK Kpp6, which has a partially redundant function with Kpp2, is also phosphorylated by Fuz7. We show that Rok1, a putative dual specificity phosphatase for MAPK signalling, controls the phosphorylation of Kpp2 as well as of Kpp6. rok1 mutants display increased filamentation and are enhanced in virulence. The enhanced virulence is caused by more efficient appressorium formation as well as plant invasion. Overexpression of rok1 reduced conjugation hyphae formation and strongly attenuated pathogenicity. This places Rok1 in a negative feedback loop regulating Kpp2 and Kpp6 activity upon pheromone stimulation and plant colonization.
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Affiliation(s)
- Maurizio Di Stasio
- Max Planck Institute for Terrestrial Microbiology, Department Organismic Interactions, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany
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25
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Bayram Ö, Sari F, Braus GH, Irniger S. The protein kinase ImeB is required for light-mediated inhibition of sexual development and for mycotoxin production inAspergillus nidulans. Mol Microbiol 2009; 71:1278-95. [DOI: 10.1111/j.1365-2958.2009.06606.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Cánovas D, Pérez-Martín J. Sphingolipid biosynthesis is required for polar growth in the dimorphic phytopathogen Ustilago maydis. Fungal Genet Biol 2009; 46:190-200. [DOI: 10.1016/j.fgb.2008.11.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 10/21/2008] [Accepted: 11/03/2008] [Indexed: 10/21/2022]
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27
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Mielnichuk N, Pérez-Martín J. 14-3-3 regulates the G2/M transition in the basidiomycete Ustilago maydis. Fungal Genet Biol 2008; 45:1206-15. [DOI: 10.1016/j.fgb.2008.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 05/19/2008] [Accepted: 05/20/2008] [Indexed: 01/04/2023]
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28
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Zarnack K, Eichhorn H, Kahmann R, Feldbrügge M. Pheromone-regulated target genes respond differentially to MAPK phosphorylation of transcription factor Prf1. Mol Microbiol 2008; 69:1041-53. [PMID: 18627457 DOI: 10.1111/j.1365-2958.2008.06345.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Pheromone signalling during mating is essential for pathogenicity of Ustilago maydis. The activity of the key transcription factor Prf1 is controlled at the transcriptional level and post-translationally by mitogen-activated protein kinase (MAPK) and protein kinase A (PKA) phosphorylation. However, the precise contribution of these regulatory mechanisms to the transcriptional output is unknown. Here, we genetically dissected the three levels of Prf1 regulation. We performed transcriptional profiling of respective mutants to identify and classify targets. This approach revealed that transcriptional regulation of prf1 had only minor influence on target gene expression stressing the importance of post-translational control. PKA regulation of Prf1 was sufficient to control expression of nine pheromone-responsive genes including the major transcription factor regulating pathogenicity. MAPK regulation was necessary for the pheromone response of a set of 57 genes. In 35 cases, pheromone responsiveness was completely lost, while in the remaining 22 cases regulation was alleviated. This indicated a novel level of complexity in MAPK signalling suggesting that target genes respond differentially to MAPK phosphorylation of the respective transcription factors.
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Affiliation(s)
- Kathi Zarnack
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, Marburg, Germany
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29
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Sari F, Heinrich M, Meyer W, Braus GH, Irniger S. The C-terminal region of the meiosis-specific protein kinase Ime2 mediates protein instability and is required for normal spore formation in budding yeast. J Mol Biol 2008; 378:31-43. [PMID: 18339400 DOI: 10.1016/j.jmb.2008.02.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2007] [Revised: 01/24/2008] [Accepted: 02/01/2008] [Indexed: 01/09/2023]
Abstract
The cyclin-dependent kinase Cdk1 and the related kinase Ime2 act in concert to trigger progression of the meiotic cell cycle in the yeast Saccharomyces cerevisiae. These kinases share several functions and substrates during meiosis, but their regulation seems to be clearly different. In contrast to Cdk1, no cyclin seems to be involved in the regulation of Ime2 activity. Ime2 is a highly unstable protein, and we aimed to elucidate the relevance of Ime2 instability. We first determined the sequence elements required for Ime2 instability by constructing a set of deletions in the IME2 gene. None of the small deletions in Ime2 affected its instability, but deletion of a 241 amino acid C-terminal region resulted in a highly stabilized protein. Thus, the C-terminal domain of Ime2 is important for mediating protein instability. The stabilized, truncated Ime2 protein is highly active in vivo. Replacement of the IME2 gene with the truncated IME2DeltaC241 in diploid strains did not interfere with meiotic nuclear divisions, but caused abnormalities in spore formation, as manifested by the appearance of many asci with a reduced spore number such as triads and dyads. The truncated Ime2 caused a reduction of spore number in a dominant manner. We conclude that downregulation of Ime2 kinase activity mediated by the C-terminal domain is required for the efficient production of normal four-spore asci. Our data suggest a role for Ime2 in spore number control in S. cerevisiae.
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Affiliation(s)
- Fatih Sari
- Institute of Microbiology and Genetics, Georg-August-University, Grisebachstr. 8, D-37077 Göttingen, Germany
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30
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Flor-Parra I, Castillo-Lluva S, Pérez-Martín J. Polar growth in the infectious hyphae of the phytopathogen ustilago maydis depends on a virulence-specific cyclin. THE PLANT CELL 2007; 19:3280-96. [PMID: 17921314 PMCID: PMC2174706 DOI: 10.1105/tpc.107.052738] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 09/07/2007] [Accepted: 09/19/2007] [Indexed: 05/14/2023]
Abstract
The maize smut fungus Ustilago maydis switches from yeast to hyphal growth to infect maize (Zea mays) plants. This switching is promoted by mating of compatible cells and seems to be required for plant penetration. Although many genes distinctively expressed during this dimorphic switch have been identified and shown to be essential for the infection process, none seems to be explicitly required for polar growth control. Here, we report the characterization of pcl12, encoding a cyclin that interacts specifically with Cdk5, an essential cyclin-dependent kinase with regulatory roles in morphogenesis in U. maydis. Pcl12 fulfills the requirements to be a virulence-specific regulator of polar growth in U. maydis. First, pcl12 expression is induced during the pathogenic development. Secondly, Pcl12 is sufficient to induce hyperpolarized growth in U. maydis cells, as haploid cells overexpressing pcl12 in axenic conditions produce filaments that were morphologically indistinguishable from those produced during the infection process. Finally, cells defective in pcl12 showed impaired polar growth during the formation of the b-dependent filament, the induction of the conjugation tubes, or the formation of a promycelium in spore germination. However, in spite of this pivotal role during morphogenesis, pcl12 mutants were virulent. We discuss the implications of these results for the role of polar growth during the infection process.
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Affiliation(s)
- Ignacio Flor-Parra
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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Klosterman SJ, Perlin MH, Garcia-Pedrajas M, Covert SF, Gold SE. Genetics of morphogenesis and pathogenic development of Ustilago maydis. ADVANCES IN GENETICS 2007; 57:1-47. [PMID: 17352901 DOI: 10.1016/s0065-2660(06)57001-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ustilago maydis has emerged as an important model system for the study of fungi. Like many fungi, U. maydis undergoes remarkable morphological transitions throughout its life cycle. Fusion of compatible, budding, haploid cells leads to the production of a filamentous dikaryon that penetrates and colonizes the plant, culminating in the production of diploid teliospores within fungal-induced plant galls or tumors. These dramatic morphological transitions are controlled by components of various signaling pathways, including the pheromone-responsive MAP kinase and cAMP/PKA (cyclic AMP/protein kinase A) pathways, which coregulate the dimorphic switch and sexual development of U. maydis. These signaling pathways must somehow cooperate with the regulation of the cytoskeletal and cell cycle machinery. In this chapter, we provide an overview of these processes from pheromone perception and mating to gall production and sporulation in planta. Emphasis is placed on the genetic determinants of morphogenesis and pathogenic development of U. maydis and on the fungus-host interaction. Additionally, we review advances in the development of tools to study U. maydis, including the recently available genome sequence. We conclude with a brief assessment of current challenges and future directions for the genetic study of U. maydis.
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Affiliation(s)
- Steven J Klosterman
- Department of Plant Pathology, University of Georgia, Athens, Georgia 30602, USA
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Zarnack K, Maurer S, Kaffarnik F, Ladendorf O, Brachmann A, Kämper J, Feldbrügge M. Tetracycline-regulated gene expression in the pathogen Ustilago maydis. Fungal Genet Biol 2006; 43:727-38. [PMID: 16843015 DOI: 10.1016/j.fgb.2006.05.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 05/02/2006] [Accepted: 05/21/2006] [Indexed: 10/24/2022]
Abstract
A powerful approach to explore gene function is the use of tetracycline-regulated expression. Here, we report the establishment of this titratable gene expression system for Ustilago maydis. Obstacles of premature polyadenylation of the native tetR gene, high basal activity of the tetracycline-responsive promoter, and toxicity of the viral activation domain were overcome by designing a synthetic tetR* gene according to context-dependent codon usage, removing cryptic enhancer elements from the promoter, and using an acidic minimal activation domain, respectively. We verified tetracycline-dependent dose-response using optimised components and applied a straightforward single-step promoter replacement cassette to regulate expression of pheromone response factor, a key transcription factor regulating mating. Pheromone response in liquid culture and mating on solid media was abolished in the presence of tetracycline and doxycycline. Thus, functionality of this versatile new tool for the plant pathogen was proven in a biological context.
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Affiliation(s)
- Kathi Zarnack
- Max-Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
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Flor-Parra I, Vranes M, Kämper J, Pérez-Martín J. Biz1, a zinc finger protein required for plant invasion by Ustilago maydis, regulates the levels of a mitotic cyclin. THE PLANT CELL 2006; 18:2369-87. [PMID: 16905655 PMCID: PMC1560913 DOI: 10.1105/tpc.106.042754] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 06/16/2006] [Accepted: 07/17/2006] [Indexed: 05/11/2023]
Abstract
Plant invasion by pathogenic fungi involves regulated growth and highly organized fungal morphological changes. For instance, when the smut fungus Ustilago maydis infects maize (Zea mays), its dikaryotic infective filament is cell cycle arrested, and appressoria are differentiated prior to plant penetration. Once the filament enters the plant, the cell cycle block is released and fungal cells begin proliferation, suggesting a tight interaction between plant invasion and the cell cycle and morphogenesis control systems. We describe a novel factor, Biz1 (b-dependent zinc finger protein), which has two Cys(2)His(2) zinc finger domains and nuclear localization, suggesting a transcriptional regulatory function. The deletion of biz1 shows no detectable phenotypic alterations during axenic growth. However, mutant cells show a severe reduction in appressoria formation and plant penetration, and those hyphae that invade the plant arrest their pathogenic development directly after plant penetration. biz1 is induced via the b-mating-type locus, the key control instance for pathogenic development. The gene is expressed at high levels throughout pathogenic development, which induces a G2 cell cycle arrest that is a direct consequence of the downregulation of the mitotic cyclin Clb1. Our data support a model in which Biz1 is involved in cell cycle arrest preceding plant penetration as well as in the induction of appressoria.
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Affiliation(s)
- Ignacio Flor-Parra
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Campus de Cantoblanco, Universidad Autonoma de Madrid, 28049 Madrid, Spain
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Pérez-Martín J, Castillo-Lluva S, Sgarlata C, Flor-Parra I, Mielnichuk N, Torreblanca J, Carbó N. Pathocycles: Ustilago maydis as a model to study the relationships between cell cycle and virulence in pathogenic fungi. Mol Genet Genomics 2006; 276:211-29. [PMID: 16896795 DOI: 10.1007/s00438-006-0152-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Accepted: 07/05/2006] [Indexed: 12/20/2022]
Abstract
Activation of virulence in pathogenic fungi often involves differentiation processes that need the reset of the cell cycle and induction of a new morphogenetic program. Therefore, the fungal capability to modify its cell cycle constitutes an important determinant in carrying out a successful infection. The dimorphic fungus Ustilago maydis is the causative agent of corn smut disease and has lately become a highly attractive model in addressing fundamental questions about development in pathogenic fungi. The different morphological and genetic changes of U. maydis cells during the pathogenic process advocate an accurate control of the cell cycle in these transitions. This is why this model pathogen deserves attention as a powerful tool in analyzing the relationships between cell cycle, morphogenesis, and pathogenicity. The aim of this review is to summarize recent advances in the unveiling of cell cycle regulation in U. maydis. We also discuss the connection between cell cycle and virulence and how cell cycle control is an important downstream target in the fungus-plant interaction.
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Affiliation(s)
- José Pérez-Martín
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología-CSIC, Campus de Cantoblanco-UAM, 28049, Madrid, Spain.
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Castillo-Lluva S, Pérez-Martín J. The induction of the mating program in the phytopathogen Ustilago maydis is controlled by a G1 cyclin. THE PLANT CELL 2005; 17:3544-60. [PMID: 16258033 PMCID: PMC1315387 DOI: 10.1105/tpc.105.036319] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Our understanding of how cell cycle regulation and virulence are coordinated during the induction of fungal pathogenesis is limited. In the maize smut fungus Ustilago maydis, pathogenesis and sexual development are intricately interconnected. Furthermore, the first step in the infection process is mating, and this is linked to the cell cycle. In this study, we have identified a new G1 cyclin gene from U. maydis that we have named cln1. We investigated the roles of Cln1 in growth and differentiation in U. maydis and found that although not essential for growth, its absence produces dramatic morphological defects. We provide results that are consistent with Cln1 playing a conserved role in regulating the length of G1 and cell size, but also additional morphological functions. We also present experiments indicating that the cyclin Cln1 controls sexual development in U. maydis. Overexpression of cln1 blocks sexual development, while its absence enables the cell to express sexual determinants in conditions where wild-type cells were unable to initiate this developmental program. We conclude that Cln1 contributes to negative regulation of the timing of sexual development, and we propose the existence of a negative crosstalk between mating program and vegetative growth that may help explain why these two developmental options are incompatible in U. maydis.
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Affiliation(s)
- Sonia Castillo-Lluva
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Campus de Cantoblanco, Universidad Autónoma de Madrid, Spain
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36
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Sgarlata C, Pérez-Martín J. The cdc25 phosphatase is essential for the G2/M phase transition in the basidiomycete yeast Ustilago maydis. Mol Microbiol 2005; 58:1482-96. [PMID: 16313631 DOI: 10.1111/j.1365-2958.2005.04925.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cdc25-related phosphatases reverse the inhibitory phosphorylation of mitotic Cyclin-dependent kinases mediated by Wee1-related kinases, thereby promoting entry into mitosis. In the fission yeast, Schizosaccharomyces pombe, Cdc25 is required for entry into mitosis, while in the budding yeast Saccharomyces cerevisiae, Mih1 (the homologue of Cdc25) is not required for entry into mitosis or for viability. As these differences were linked to the different cell division and growth mechanism of these species, we sought to analyse the roles of Cdc25 in Ustilago maydis, which as S. cerevisiae divides by budding, but relies in a polar growth. This basidiomycete yeast is perfectly suited to analyse the relationships between cell cycle and morphogenesis. We show that U. maydis contains a single Cdc25-related protein, which is essential for growth. Loss of Cdc25 function results in a specific G2 arrest that correlated with high level of Tyr15 phosphorylation of Cdk1. Moreover, we show genetic interactions of cdc25 with wee1 and clb2 that support the notion that in U. maydis Cdc25 counteracts the Wee1-mediated inhibitory phosphorylation of Cdk1-Clb2 complex. Our results supports a model in which inhibitory phosphorylation of Cdk1 is a primary mechanism operating at G2/M transition in this fungus.
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Affiliation(s)
- Cecilia Sgarlata
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología CSIC, Campus de Cantoblanco-UAM, 28049 Madrid, Spain
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37
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Brefort T, Müller P, Kahmann R. The high-mobility-group domain transcription factor Rop1 is a direct regulator of prf1 in Ustilago maydis. EUKARYOTIC CELL 2005; 4:379-91. [PMID: 15701800 PMCID: PMC549323 DOI: 10.1128/ec.4.2.379-391.2005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In the smut fungus Ustilago maydis, the pheromone signal is transmitted via a mitogen-activated protein kinase module to the high-mobility-group (HMG) domain transcription factor Prf1, leading to its activation. This triggers sexual and pathogenic development since Prf1 binds to the PRE boxes located in the promoters of the a and b mating type genes. Here, we present the characterization of rop1 and hmg3, encoding two additional sequence-specific HMG domain proteins. While hmg3 mutants are slightly impaired in mating and do form conjugation hyphae, rop1 deletion strains display a severe mating and filamentation defect and do not respond to pheromone stimulation. In particular, rop1 is essential for pheromone-induced gene expression in axenic culture. Constitutive expression of prf1 fully complements the mating defect of rop1 mutants, indicating that rop1 is required for prf1 gene expression. Indeed, we could show that Rop1 binds directly to specific elements in the prf1 promoter. Surprisingly, on the plant surface, rop1 deletion strains do form conjugation hyphae and express sufficient amounts of prf1 to cause full pathogenicity. This indicates the involvement of additional components in the regulation of prf1 gene expression during pathogenic growth.
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Affiliation(s)
- Thomas Brefort
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany
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38
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Sgarlata C, Pérez-Martín J. Inhibitory phosphorylation of a mitotic cyclin-dependent kinase regulates the morphogenesis, cell size and virulence of the smut fungusUstilago maydis. J Cell Sci 2005; 118:3607-22. [PMID: 16046476 DOI: 10.1242/jcs.02499] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The regulation of cyclin-dependent kinase (CDK) activity through inhibitory phosphorylation seems to play an important role in the eukaryotic cell cycle. We have investigated the influence that inhibitory phosphorylation of the catalytic subunit of mitotic CDK has on cell growth and pathogenicity of the corn smut fungus Ustilago maydis. This model pathogen is worthy of attention since it is well suited to analyze the relationships between the cell cycle, morphogenesis and pathogenicity. We set out to study these relationships by producing a cdk1 mutant allele that was refractory to inhibitory phosphorylation. The expression of this mutant in U. maydis cells dramatically altered their morphology. Since this kind of mutation makes the CDK catalytic subunit resistant to regulation by Wee1-related kinases in other organisms, we characterized the orthologous Wee1 kinase from U. maydis. We found that Wee1 is essential in U. maydis. Overexpression of wee1 produces cell cycle arrest in G2, the target of Wee1 apparently being the Cdk1/Clb2 complex, which is required specifically for the onset of mitosis. Given the connection between the cell cycle control and pathogenesis in U. maydis, we also analyzed whether cells with impaired inhibitory phosphorylation of Cdk1 were able to infect plants. We found that inhibitory phosphorylation was required for mating, a prerequisite to initiate pathogenic development. By examining plant-specific expression of the constitutively unphosphorylated cdk1AF allele, we also found that appropriate levels of inhibitory phosphorylation were required at stages of infection subsequent to penetration by the fungus. These data reinforces the connections between cell cycle, morphogenesis and virulence in this smut fungus.
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Affiliation(s)
- Cecilia Sgarlata
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología CSIC, Campus de Cantoblanco-UAM, 28049 Madrid, Spain
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39
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Castillo-Lluva S, García-Muse T, Pérez-Martín J. A member of the Fizzy-related family of APC activators is regulated by cAMP and is required at different stages of plant infection by Ustilago maydis. J Cell Sci 2005; 117:4143-56. [PMID: 15316079 DOI: 10.1242/jcs.01304] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Here, we identified a new member of the Fizzy-related family of APC activators, Cru1, which is required for virulence in the corn smut fungus Ustilago maydis. We show that Cru1 promotes the degradation of B-type cyclins in U. maydis. Cells deficient in the Cru1 protein show defects in cell size, adaptation to nutritional conditions and cell separation. We propose that the phenotypes observed are a consequence of the inability of cru1 Delta cells to keep under control the levels of mitotic cyclins during G1. The levels of cru1 mRNA are controlled by nutritional conditions and cAMP levels, implicating the cAMP/protein kinase A pathway in the transmission of environmental conditions to the cell cycle. Cells deficient in Cru1 function are severely impaired in their ability to infect corn plants. This low rate of plant infection is caused by several defects. First, a low level of expression of the pheromone-encoding gene, mfa1, resulted in a low frequency of dikaryotic infective filament formation. Second, proliferation of fungal cells inside the plant is also affected, resulting in the inability to induce tumors in plants. Finally, the formation and germination of teliospores is also impaired. Our results support the hypothesis that virulence and cell cycle are connected in U. maydis. We propose that along the infection process, Cru1 is required to keep the appropriate G1 length necessary for the adaptation of fungal cells to host environment through the different stages of the plant infection.
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Affiliation(s)
- Sonia Castillo-Lluva
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología CSIC, Campus de Cantoblanco-UAM, 28049 Madrid, Spain
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40
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Garrido E, Voss U, Müller P, Castillo-Lluva S, Kahmann R, Pérez-Martín J. The induction of sexual development and virulence in the smut fungus Ustilago maydis depends on Crk1, a novel MAPK protein. Genes Dev 2005; 18:3117-30. [PMID: 15601825 PMCID: PMC535921 DOI: 10.1101/gad.314904] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
MAP kinases (mitogen-activated protein kinases) are activated by dual phosphorylation on specific threonine and specific tyrosine residues that are separated by a single residue, and the TXY activation motif is a hallmark of MAP kinases. In the fungus Ustilago maydis, which causes corn smut disease, the Crk1 protein, a kinase previously described to have roles in morphogenesis, carries a TXY motif that aligns with the TXY of MAP kinases. In this work, we demonstrate that Crk1 is activated through a mechanism that requires the phosphorylation of this motif. Our data show that Fuz7, a MAPK kinase involved in mating and pathogenesis in U. maydis, is required to activate Crk1, most likely through phosphorylation of the TXY motif. Consistently, we found that Crk1 is also required for mating and virulence. We investigated the reasons for sterility and avirulence of crk1-deficient cells, and we found that Crk1 is required for transcription of prf1, a central regulator of mating and pathogenicity in U. maydis. Crk1 belongs to a wide conserved protein group, whose members have not been previously defined as MAP kinases, although they carry TXY motifs. On the basis of our data, we propose that all of these proteins constitute a new family of MAP kinases.
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Affiliation(s)
- Elia Garrido
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología CSIC, Campus de Cantoblanco-UAM, 28049 Madrid, Spain
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Feldbrügge M, Kämper J, Steinberg G, Kahmann R. Regulation of mating and pathogenic development in Ustilago maydis. Curr Opin Microbiol 2005; 7:666-72. [PMID: 15556041 DOI: 10.1016/j.mib.2004.10.006] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The plant pathogenic fungus Ustilago maydis induces disease only in its dikaryotic stage that is generated after mating. This process involves coordinated cAMP and mitogen-activated protein kinase signalling to regulate transcriptional as well as morphological responses. Among the induced products is the key regulator for pathogenic development. Recent advances identified crucial nodes that interconnect these pathways. The key regulator orchestrates a complex transcriptional cascade, the components of which have been uncovered by genomic strategies. This is complemented by insights into organization, dynamics and function of the cytoskeleton, which begin to establish the links between signalling, intracellular transport processes and morphology.
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Affiliation(s)
- Michael Feldbrügge
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, D-35043 Marburg, Germany
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42
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Genetics of Morphogenesis in Basidiomycetes. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s1874-5334(05)80017-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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43
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Brachmann A, König J, Julius C, Feldbrügge M. A reverse genetic approach for generating gene replacement mutants in Ustilago maydis. Mol Genet Genomics 2004; 272:216-26. [PMID: 15316769 DOI: 10.1007/s00438-004-1047-z] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Accepted: 07/19/2004] [Indexed: 10/26/2022]
Abstract
We describe a versatile strategy for generating gene replacement mutants in the phytopathogenic fungus Ustilago maydis. The system includes the choice of 32 different insertion cassettes for genetic engineering purposes, such as gene disruption and more sophisticated insertions of reporter genes, heterologous promoters or combinations of the two. PCR-amplified flanking sequences needed for homologous recombination are ligated to the respective insertion cassettes via SfiI sites. As proof of principle we generated two replacement mutants in which the endogenous promoter of the pheromone gene mfa1 drives expression of the Green Fluorescent Protein gene (gfp). Simultaneously, expression of the mfa1 ORF is controlled either by the carbon source-regulated crg1 promoter or the nitrogen source-regulated nar1 promoter. In both cases gfp expression was pheromone-inducible and pheromone expression was only detected when the heterologous promoters were active.
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Affiliation(s)
- A Brachmann
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043, Marburg, Germany
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44
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Basse CW, Steinberg G. Ustilago maydis, model system for analysis of the molecular basis of fungal pathogenicity. MOLECULAR PLANT PATHOLOGY 2004; 5:83-92. [PMID: 20565585 DOI: 10.1111/j.1364-3703.2004.00210.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
UNLABELLED SUMMARY Ustilago maydis, a facultative biotrophic basidiomycete fungus, causes smut disease in maize. A hallmark of this disease is the induction of large plant tumours that are filled with masses of black-pigmented teliospores. During the last 15 years U. maydis has become an important model system to unravel molecular mechanisms of fungal phytopathogenicity. This review highlights recent insights into molecular mechanisms of complex signalling pathways that are involved in the transition from budding to filamentous growth and operate during the pathogenic growth phase. In addition, we describe recent progress in understanding the structural basis of morphogenesis and polar growth in different stages of U. maydis development. Finally, we present an overview of recently identified genes related to pathogenic development and summarize novel molecular and genomic approaches that are powerful tools to explore the genetic base of pathogenicity. TAXONOMY Ustilago maydis (DC) Corda (synonymous with Ustilago zeae Ung.)-Kingdom Eukaryota, Phylum Fungi, Order Basidiomycota, Family Ustilaginomycetes, Genus Ustilago. HOST RANGE Infects aerial parts of corn plants (Zea mays) and its progenitor teosinte (Zea mays ssp. parviglumis). Maize smut is distributed throughout the world. Disease symptoms: U. maydis causes chlorotic lesions in infected areas, the formation of anthocyanin pigments, necrosis, hyperplasia and hypertrophy of infected organs. Infection by U. maydis can inhibit development and lead to stunting of infected plants. A few days after infection plant tumours develop in which massive fungal proliferation and the formation of the black-pigmented, diploid teliospores occurs. Under natural conditions tumours predominantly develop on sexual organs (tassels and ears), stems and nodal shoots. Tumours may vary in size from minute pustules to several centimetres in diameter and contain up to 200 billion spores. Useful web site: http://www-genome.wi.mit.edu/annotation/fungi/ustilago_maydis/
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Affiliation(s)
- Christoph W Basse
- Max-Planck-Institute for Terrestrial Microbiology, Department of Organismic Interactions, Karl-von-Frisch Strasse, 35043 Marburg, Germany
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45
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García-Muse T, Steinberg G, Perez-Martín J. Characterization of B-type cyclins in the smut fungusUstilago maydis: roles in morphogenesis and pathogenicity. J Cell Sci 2004; 117:487-506. [PMID: 14679309 DOI: 10.1242/jcs.00877] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pathogenesis, morphogenesis and cell cycle are connected in the fungal pathogen Ustilago maydis. Here we report the characterization of the catalytic subunit of the cyclin-dependent kinase, encoded by the gene cdk1, and the two B-type cyclins present in this organism, encoded by the genes clb1 and clb2. These cyclins are not redundant and appears to be essential for cell cycle. The analysis of conditional mutants in cyclin genes indicates that Clb1 is required for G1 to S and G2 to M transitions, while Clb2 is specifically required for the onset of mitosis. Both Clb1 and Clb2 carry functional destruction boxes, and expression of derivatives lacking D-boxes arrested cell cycle at a post-replicative stage. High levels of Clb1 generated cells with anomalous DNA content that were hypersensitive to microtubule-destabilizing drugs. In contrast, high levels of Clb2 induce premature entry into mitosis, suggesting that Clb2 is a mitotic inducer in U. maydis. In addition, Clb2 affects morphogenesis, and overexpression of clb2 induces filamentous growth. Furthermore, we have found that appropriate levels of Clb2 cyclin are critical for a successful infection. Mutant strains with half a dose of clb2 or high level of clb2 expression are impaired at distinct stages in the infection process. These data reinforces the connections between cell cycle, morphogenesis and virulence in this smut fungus.
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Affiliation(s)
- Tatiana García-Muse
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología CSIC, Campus de Cantoblanco-UAM, 28049 Madrid, Spain
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46
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Ladendorf O, Brachmann A, Kämper J. Heterologous transposition in Ustilago maydis. Mol Genet Genomics 2003; 269:395-405. [PMID: 12734750 DOI: 10.1007/s00438-003-0848-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2002] [Accepted: 03/31/2003] [Indexed: 11/25/2022]
Abstract
The phytopathogenic basidiomycete Ustilago maydis has become a model system for the analysis of plant-pathogen interactions. The genome sequence of this organism will soon be available, increasing the need for techniques to analyse gene function on a broad basis. We describe a heterologous transposition system for U. maydis that is based on the Caenorhabditis transposon Tc1, which is known to function independently of host factors and to be active in evolutionarily distant species. We have established a nitrate reductase based two-component counterselection system to screen for Tc1 transposition. The element was shown to be functional and transposed to several different locations in the genome of U. maydis. The insertion pattern observed was consistent with the proposed general mechanism of Tc1/mariner integration and constitutes a proof of principle for the first heterologous transposition system in a basidiomycete species. By mapping the insertion site context to known genomic sequences, Tc1 insertion events were shown to occur on different chromosomes, but exhibit a preference for non-coding regions. Only 20% of the insertions were found in putative open reading frames. The establishment of this system will permit efficient gene tagging in U. maydis and possibly also in other fungi.
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Affiliation(s)
- O Ladendorf
- Max-Planck-Institut für terrestrische Mikrobiologie, Karl-von-Frisch Str., 35043 Marburg, Germany
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García-Muse T, Steinberg G, Pérez-Martín J. Pheromone-induced G2 arrest in the phytopathogenic fungus Ustilago maydis. EUKARYOTIC CELL 2003; 2:494-500. [PMID: 12796294 PMCID: PMC161457 DOI: 10.1128/ec.2.3.494-500.2003] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the corn smut fungus Ustilago maydis, pathogenic development is initiated when two compatible haploid cells fuse and form the infectious dikaryon. Mating is dependent on pheromone recognition by compatible cells. In this report, we set out to evaluate the relationship between the cell cycle and the pheromone response in U. maydis. To achieve this, we designed a haploid pheromone-responsive strain that is able to faithfully reproduce the native mating response in nutrient-rich medium. Addition of synthetic pheromone to the responsive strain induces the formation of mating structures, and this response is abolished by mutations in genes encoding components of the pheromone signal transduction cascade. After recognition of pheromone, U. maydis cells arrest the cell cycle in a postreplicative stage. Visualization of the nucleus and microtubule organization indicates that the arrest takes place at the G(2) phase. Chemical-induced cell cycle arrest and release in the presence of pheromone further support this conclusion.
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Affiliation(s)
- Tatiana García-Muse
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología CSIC, Campus de Cantoblanco-UAM, 28049 Madrid, Spain
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