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Mongès A, Yaakoub H, Bidon B, Glévarec G, Héricourt F, Carpin S, Chauderon L, Drašarová L, Spíchal L, Binder BM, Papon N, Rochange S. Are Histidine Kinases of Arbuscular Mycorrhizal Fungi Involved in the Response to Ethylene and Cytokinins? MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:656-665. [PMID: 37851914 DOI: 10.1094/mpmi-05-23-0056-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Signals are exchanged at all stages of the arbuscular mycorrhizal (AM) symbiosis between fungi and their host plants. Root-exuded strigolactones are well-known early symbiotic cues, but the role of other phytohormones as interkingdom signals has seldom been investigated. Here we focus on ethylene and cytokinins, for which candidate receptors have been identified in the genome of the AM fungus Rhizophagus irregularis. Ethylene is known from the literature to affect asymbiotic development of AM fungi, and in the present study, we found that three cytokinin forms could stimulate spore germination in R. irregularis. Heterologous complementation of a Saccharomyces cerevisiae mutant strain with the candidate ethylene receptor RiHHK6 suggested that this protein can sense and transduce an ethylene signal. Accordingly, its N-terminal domain expressed in Pichia pastoris displayed saturable binding to radiolabeled ethylene. Thus, RiHHK6 displays the expected characteristics of an ethylene receptor. In contrast, the candidate cytokinin receptor RiHHK7 did not complement the S. cerevisiae mutant strain or Medicago truncatula cytokinin receptor mutants and seemed unable to bind cytokinins, suggesting that another receptor is involved in the perception of these phytohormones. Taken together, our results support the hypothesis that AM fungi respond to a range of phytohormones and that these compounds bear multiple functions in the rhizosphere beyond their known roles as internal plant developmental regulators. Our analysis of two phytohormone receptor candidates also sheds new light on the possible perception mechanisms in AM fungi. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Ayla Mongès
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, Centre National de la Recherche Scientifique, Université Paul Sabatier, INP Toulouse, 31326 Castanet-Tolosan, France
| | - Hajar Yaakoub
- UNIV Angers, IRF, SFR 4208 ICAT, F-49000 Angers, France
| | | | - Gaëlle Glévarec
- EA2106 Biomolécules et Biotechnologies Végétales, Université de Tours, Tours, France
| | - François Héricourt
- Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Université d'Orléans, INRAE USC1328, 45067 Orléans Cedex 2, France
| | - Sabine Carpin
- Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Université d'Orléans, INRAE USC1328, 45067 Orléans Cedex 2, France
| | - Lucie Chauderon
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, Centre National de la Recherche Scientifique, Université Paul Sabatier, INP Toulouse, 31326 Castanet-Tolosan, France
| | - Lenka Drašarová
- Isotope Laboratory, Institute of Experimental Botany, The Czech Academy of Sciences, Vídeňská, 1083, Prague, Czech Republic
| | - Lukáš Spíchal
- Czech Advanced Technology and Research Institute, Šlechtitelů 27, Olomouc CZ-783 71, Palacký University, Olomouc, Czech Republic
| | - Brad M Binder
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, U.S.A
| | - Nicolas Papon
- UNIV Angers, IRF, SFR 4208 ICAT, F-49000 Angers, France
| | - Soizic Rochange
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, Centre National de la Recherche Scientifique, Université Paul Sabatier, INP Toulouse, 31326 Castanet-Tolosan, France
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The Sporisorium reilianum Effector Vag2 Promotes Head Smut Disease via Suppression of Plant Defense Responses. J Fungi (Basel) 2022; 8:jof8050498. [PMID: 35628753 PMCID: PMC9146561 DOI: 10.3390/jof8050498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 01/27/2023] Open
Abstract
Genome comparison between the maize pathogens Ustilago maydis and Sporisorium reilianum revealed a large diversity region (19-1) containing nearly 30 effector gene candidates, whose deletion severely hampers virulence of both fungi. Dissection of the S. reilianum gene cluster resulted in the identification of one major contributor to virulence, virulence-associated gene 2 (vag2; sr10050). Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) experiments revealed high expression of vag2 during biotrophic growth of S. reilianum. Using the yeast secretion trap assay, we confirmed the existence of a functional signal peptide allowing protein secretion via the conventional secretory pathway. We identified the cytoplasmic maize chorismate mutase ZmCM2 by yeast two-hybrid screening as a possible interaction partner of Vag2. Interaction of the two proteins in planta was confirmed by bimolecular fluorescence complementation. qRT-PCR experiments revealed vag2-dependent downregulation of salicylic acid (SA)-induced genes, which correlated with higher SA levels in plant tissues colonized by Δvag2 deletion strains relative to S. reilianum wildtype strains. Metabolite analysis suggested rewiring of pathogen-induced SA biosynthesis by preferential conversion of the SA precursor chorismate into the aromatic amino acid precursor prephenate by ZmCM2 in the presence of Vag2. Possibly, the binding of Vag2 to ZmCM2 inhibits the back reaction of the ZmCM2-catalyzed interconversion of chorismate and prephenate, thus contributing to fungal virulence by lowering the plant SA-induced defenses.
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Syrova DS, Shaposhnikov AI, Yuzikhin OS, Belimov AA. Destruction and Transformation of Phytohormones By Microorganisms. APPL BIOCHEM MICRO+ 2022. [DOI: 10.1134/s0003683822010094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Alcântara A, Seitner D, Navarrete F, Djamei A. A high-throughput screening method to identify proteins involved in unfolded protein response of the endoplasmic reticulum in plants. PLANT METHODS 2020; 16:4. [PMID: 31988651 PMCID: PMC6971872 DOI: 10.1186/s13007-020-0552-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/08/2020] [Indexed: 05/26/2023]
Abstract
BACKGROUND The unfolded protein response (UPR) is a highly conserved process in eukaryotic organisms that plays a crucial role in adaptation and development. While the most ubiquitous components of this pathway have been characterized, current efforts are focused on identifying and characterizing other UPR factors that play a role in specific conditions, such as developmental changes, abiotic cues, and biotic interactions. Considering the central role of protein secretion in plant pathogen interactions, there has also been a recent focus on understanding how pathogens manipulate their host's UPR to facilitate infection. RESULTS We developed a high-throughput screening assay to identify proteins that interfere with UPR signaling in planta. A set of 35 genes from a library of secreted proteins from the maize pathogen Ustilago maydis were transiently co-expressed with a reporter construct that upregulates enhanced yellow fluorescent protein (eYFP) expression upon UPR stress in Nicotiana benthamiana plants. After UPR stress induction, leaf discs were placed in 96 well plates and eYFP expression was measured. This allowed us to identify a previously undescribed fungal protein that inhibits plant UPR signaling, which was then confirmed using the classical but more laborious qRT-PCR method. CONCLUSIONS We have established a rapid and reliable fluorescence-based method to identify heterologously expressed proteins involved in UPR stress in plants. This system can be used for initial screens with libraries of proteins and potentially other molecules to identify candidates for further validation and characterization.
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Affiliation(s)
- André Alcântara
- Gregor Mendel Institute of Molecular Plant Biology, Vienna, Austria
| | - Denise Seitner
- Gregor Mendel Institute of Molecular Plant Biology, Vienna, Austria
| | | | - Armin Djamei
- Gregor Mendel Institute of Molecular Plant Biology, Vienna, Austria
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Gatersleben, Germany
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Hao G, Naumann TA, Vaughan MM, McCormick S, Usgaard T, Kelly A, Ward TJ. Characterization of a Fusarium graminearum Salicylate Hydroxylase. Front Microbiol 2019; 9:3219. [PMID: 30671040 PMCID: PMC6331432 DOI: 10.3389/fmicb.2018.03219] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/11/2018] [Indexed: 11/13/2022] Open
Abstract
Salicylic acid (SA) plays an important role in regulating plant defense responses against pathogens. However, pathogens have evolved ways to manipulate plant SA-mediated defense signaling. Fusarium graminearum causes Fusarium head blight (FHB) and reduces crop yields and quality by producing various mycotoxins. In this study, we aimed to identify the salicylate hydroxylase in F. graminearum and determine its role in wheat head blight development. We initially identified a gene in F. graminearum strain NRRL 46422 that encodes a putative salicylate hydroxylase (designated FgShyC). However, the FgShyC deletion mutant showed a similar ability to degrade SA as wild-type strain 46422; nor did overexpression of FgShyC in E. coli convert SA to catechol. The results indicate that FgShyC is not involved in SA degradation. Further genome sequence analyses resulted in the identification of eight salicylate hydroxylase candidates. Upon addition of 1 mM SA, FGSG_03657 (designated FgShy1), was induced approximately 400-fold. Heterologous expression of FgShy1 in E. coli converted SA to catechol, confirming that FgShy1 is a salicylate hydroxylase. Deletion mutants of FgShy1 were greatly impaired but not completely blocked in SA degradation. Expression analyses of infected tissue showed that FgShy1 was induced during infection, but virulence assays revealed that deletion of FgShy1 alone was not sufficient to affect FHB severity. Although the Fgshy1 deletion mutant did not reduce pathogenicity, we cannot rule out that additional salicylate hydroxylases are present in F. graminearum and characterization of these enzymes will be necessary to fully understand the role of SA-degradation in FHB pathogenesis.
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Affiliation(s)
- Guixia Hao
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture – Agricultural Research Service, Peoria, IL, United States
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Rocheleau H, Al-Harthi R, Ouellet T. Degradation of salicylic acid by Fusarium graminearum. Fungal Biol 2018; 123:77-86. [PMID: 30654960 DOI: 10.1016/j.funbio.2018.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 10/23/2018] [Accepted: 11/08/2018] [Indexed: 12/20/2022]
Abstract
Fusarium head blight (FHB) is a major cereal crop disease, caused most frequently by the fungus Fusarium graminearum. We have previously demonstrated that F. graminearum can utilize SA as sole source of carbon to grow. In this current study, we further characterized selected four fungal SA-responsive genes that are predicted to encode salicylic acid (SA)-degrading enzymes and we used a gene replacement approach to characterize them further. These included two genes predicted to encode a salicylate 1-monooxygenase, FGSG_03657 and FGSG_09063, a catechol 1, 2-dioxygenase gene, FGSG_03667, and a 2, 3-dihydroxybenzoic acid decarboxylase gene, FGSG_09061. For each gene, three independent gene replacement strains were assayed for their ability to degrade salicylic acid in liquid culture. Salicylate 1-monooxygenase FGSG_03657 and catechol 1, 2-dioxygenase FGSG_03667 were shown to be essential for SA degradation, while a loss of 2, 3-dihydroxybenzoic acid decarboxylase FGSG_09061 caused only a partial reduction of SA degradation and a loss of salicylate 1-monooxygenase FGSG_09063 had no effect when compared to wild type culture. Salicylate 1-monooxygenase FGSG_03657 and catechol 1, 2-dioxygenase FGSG_03667 were identified as the first two key enzyme steps of SA degradation via catechol in the β-ketoadipate pathway. Expression profiles for all four genes were also determined in liquid culture and in planta. Salicylate 1-monooxygenase FGSG_03657 and catechol 1, 2-dioxygenase FGSG_03667 were co-expressed and their expression was substrate dependent in liquid culture; however their expression was uncoupled in planta. Disruption of the gene for catechol 1, 2-dioxygenase FGSG_03667 was shown to have no effect on fungal virulence on wheat. Our results with 2, 3-dihydroxybenzoic acid decarboxylase FGSG_09061 raise the possibility of an alternate non-oxidative decarboxylation pathway for the conversion of SA to catechol via 2, 3-dihydrozybenzoic acid and for a connection between the oxidative and the non-oxidative decarboxylation pathways for SA conversion.
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Affiliation(s)
- Hélène Rocheleau
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Ave, Ottawa, ON K1A 0C6, Canada.
| | - Reem Al-Harthi
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Ave, Ottawa, ON K1A 0C6, Canada; Department of Biology, University of Ottawa, 30 Marie Currie, Ottawa, ON K1N 6N5, Canada.
| | - Thérèse Ouellet
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Ave, Ottawa, ON K1A 0C6, Canada.
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Seitner D, Uhse S, Gallei M, Djamei A. The core effector Cce1 is required for early infection of maize by Ustilago maydis. MOLECULAR PLANT PATHOLOGY 2018; 19:2277-2287. [PMID: 29745456 PMCID: PMC6638113 DOI: 10.1111/mpp.12698] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The biotrophic pathogen Ustilago maydis, the causative agent of corn smut disease, infects one of the most important crops worldwide - Zea mays. To successfully colonize its host, U. maydis secretes proteins, known as effectors, that suppress plant defense responses and facilitate the establishment of biotrophy. In this work, we describe the U. maydis effector protein Cce1. Cce1 is essential for virulence and is upregulated during infection. Through microscopic analysis and in vitro assays, we show that Cce1 is secreted from hyphae during filamentous growth of the fungus. Strikingly, Δcce1 mutants are blocked at early stages of infection and induce callose deposition as a plant defense response. Cce1 is highly conserved among smut fungi and the Ustilago bromivora ortholog complemented the virulence defect of the SG200Δcce1 deletion strain. These data indicate that Cce1 is a core effector with apoplastic localization that is essential for U. maydis to infect its host.
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Affiliation(s)
- Denise Seitner
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC)Vienna1030Austria
| | - Simon Uhse
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC)Vienna1030Austria
| | - Michelle Gallei
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC)Vienna1030Austria
- Institute of Science and Technology AustriaKlosterneuburg3400Austria
| | - Armin Djamei
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC)Vienna1030Austria
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Uhse S, Pflug FG, Stirnberg A, Ehrlinger K, von Haeseler A, Djamei A. In vivo insertion pool sequencing identifies virulence factors in a complex fungal-host interaction. PLoS Biol 2018; 16:e2005129. [PMID: 29684023 PMCID: PMC5912717 DOI: 10.1371/journal.pbio.2005129] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/20/2018] [Indexed: 12/15/2022] Open
Abstract
Large-scale insertional mutagenesis screens can be powerful genome-wide tools if they are streamlined with efficient downstream analysis, which is a serious bottleneck in complex biological systems. A major impediment to the success of next-generation sequencing (NGS)-based screens for virulence factors is that the genetic material of pathogens is often underrepresented within the eukaryotic host, making detection extremely challenging. We therefore established insertion Pool-Sequencing (iPool-Seq) on maize infected with the biotrophic fungus U. maydis. iPool-Seq features tagmentation, unique molecular barcodes, and affinity purification of pathogen insertion mutant DNA from in vivo-infected tissues. In a proof of concept using iPool-Seq, we identified 28 virulence factors, including 23 that were previously uncharacterized, from an initial pool of 195 candidate effector mutants. Because of its sensitivity and quantitative nature, iPool-Seq can be applied to any insertional mutagenesis library and is especially suitable for genetically complex setups like pooled infections of eukaryotic hosts.
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Affiliation(s)
- Simon Uhse
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Florian G. Pflug
- Center for Integrative Bioinformatics Vienna (CIBIV), Max F Perutz Laboratories (MFPL), University of Vienna, Medical University Vienna, Vienna, Austria
| | - Alexandra Stirnberg
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Klaus Ehrlinger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Arndt von Haeseler
- Center for Integrative Bioinformatics Vienna (CIBIV), Max F Perutz Laboratories (MFPL), University of Vienna, Medical University Vienna, Vienna, Austria
- Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria
| | - Armin Djamei
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
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Lanver D, Müller AN, Happel P, Schweizer G, Haas FB, Franitza M, Pellegrin C, Reissmann S, Altmüller J, Rensing SA, Kahmann R. The Biotrophic Development of Ustilago maydis Studied by RNA-Seq Analysis. THE PLANT CELL 2018; 30:300-323. [PMID: 29371439 PMCID: PMC5868686 DOI: 10.1105/tpc.17.00764] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 12/20/2017] [Accepted: 01/24/2018] [Indexed: 05/19/2023]
Abstract
The maize smut fungus Ustilago maydis is a model organism for elucidating host colonization strategies of biotrophic fungi. Here, we performed an in depth transcriptional profiling of the entire plant-associated development of U. maydis wild-type strains. In our analysis, we focused on fungal metabolism, nutritional strategies, secreted effectors, and regulatory networks. Secreted proteins were enriched in three distinct expression modules corresponding to stages on the plant surface, establishment of biotrophy, and induction of tumors. These modules are likely the key determinants for U. maydis virulence. With respect to nutrient utilization, we observed that expression of several nutrient transporters was tied to these virulence modules rather than being controlled by nutrient availability. We show that oligopeptide transporters likely involved in nitrogen assimilation are important virulence factors. By measuring the intramodular connectivity of transcription factors, we identified the potential drivers for the virulence modules. While known components of the b-mating type cascade emerged as inducers for the plant surface and biotrophy module, we identified a set of yet uncharacterized transcription factors as likely responsible for expression of the tumor module. We demonstrate a crucial role for leaf tumor formation and effector gene expression for one of these transcription factors.
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Affiliation(s)
- Daniel Lanver
- Max-Planck-Institut für Terrestrische Mikrobiologie, Abteilung Organismische Interaktionen, 35043 Marburg, Germany
| | - André N Müller
- Max-Planck-Institut für Terrestrische Mikrobiologie, Abteilung Organismische Interaktionen, 35043 Marburg, Germany
| | - Petra Happel
- Max-Planck-Institut für Terrestrische Mikrobiologie, Abteilung Organismische Interaktionen, 35043 Marburg, Germany
| | - Gabriel Schweizer
- Max-Planck-Institut für Terrestrische Mikrobiologie, Abteilung Organismische Interaktionen, 35043 Marburg, Germany
| | - Fabian B Haas
- Philipps Universität Marburg, Fb17 Biologie, AG Zellbiologie der Pflanzen, 35043 Marburg, Germany
| | - Marek Franitza
- Cologne Center for Genomics, University of Cologne, 50931 Cologne, Germany
| | - Clément Pellegrin
- Max-Planck-Institut für Terrestrische Mikrobiologie, Abteilung Organismische Interaktionen, 35043 Marburg, Germany
| | - Stefanie Reissmann
- Max-Planck-Institut für Terrestrische Mikrobiologie, Abteilung Organismische Interaktionen, 35043 Marburg, Germany
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
| | - Stefan A Rensing
- Philipps Universität Marburg, Fb17 Biologie, AG Zellbiologie der Pflanzen, 35043 Marburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Regine Kahmann
- Max-Planck-Institut für Terrestrische Mikrobiologie, Abteilung Organismische Interaktionen, 35043 Marburg, Germany
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Abstract
Biotrophic fungal plant pathogens establish an intimate relationship with their host to support the infection process. Central to this strategy is the secretion of a range of protein effectors that enable the pathogen to evade plant immune defences and modulate host metabolism to meet its needs. In this Review, using the smut fungus Ustilago maydis as an example, we discuss new insights into the effector repertoire of smut fungi that have been gained from comparative genomics and discuss the molecular mechanisms by which U. maydis effectors change processes in the plant host. Finally, we examine how the expression of effector genes and effector secretion are coordinated with fungal development in the host.
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