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Qi M, Yu H, Bredow M, Chicowski AS, Fields LD, Whitham SA. Insights into Phakopsora pachyrhizi Effector-Effector Interactions. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:227-231. [PMID: 37831963 DOI: 10.1094/mpmi-08-23-0120-fi] [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: 10/15/2023]
Abstract
The multifaceted role of pathogen-encoded effectors in plant-pathogen interactions is complex and not fully understood. Effectors operate within intricate host environments, interacting with host proteins and other effectors to modulate virulence. The complex interplay between effectors raises the concept of metaeffectors, wherein some effectors regulate the activity of others. While previous research has demonstrated the importance of effector repertoires in pathogen virulence, only a limited number of studies have investigated the interactions between these effectors. This study explores the interactions among Phakopsora pachyrhizi effector candidates (PpECs). P. pachyrhizi haustorial transcriptome analysis identified a collection of predicted PpECs. Among these, PpEC23 was found to interact with PpEC48, prompting further exploration into their potential interaction with other effectors. Here, we utilized a yeast two-hybrid screen to explore protein-protein interactions between PpECs. A split-luciferase complementation assay also demonstrated that these interactions could occur within soybean cells. Interestingly, PpEC48 displayed the ability to interact with several small cysteine-rich proteins (SCRPs), suggesting its affinity for this specific class of effectors. We show that these interactions involve a histidine-rich domain within PpEC48, emphasizing the significance of structural motifs in mediating effector interactions. The unique nature of PpEC48, showing no sequence matches in other organisms, suggests its relatively recent evolution and potential orphan gene status. Our work reveals insights into the intricate network of interactions among P. pachyrhizi effector-effector interactions. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Mingsheng Qi
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA 50011, U.S.A
| | - Haiyue Yu
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA 50011, U.S.A
- State Key Laboratory of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, China Agricultural University, 100193, Beijing, China
| | - Melissa Bredow
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA 50011, U.S.A
| | - Aline Sartor Chicowski
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA 50011, U.S.A
| | - Letícia Dias Fields
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA 50011, U.S.A
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), 91501-970, Porto Alegre, RS, Brazil
| | - Steven A Whitham
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA 50011, U.S.A
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2
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Stuer N, Van Damme P, Goormachtig S, Van Dingenen J. Seeking the interspecies crosswalk for filamentous microbe effectors. TRENDS IN PLANT SCIENCE 2023; 28:1045-1059. [PMID: 37062674 DOI: 10.1016/j.tplants.2023.03.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 03/02/2023] [Accepted: 03/18/2023] [Indexed: 06/19/2023]
Abstract
Both pathogenic and symbiotic microorganisms modulate the immune response and physiology of their host to establish a suitable niche. Key players in mediating colonization outcome are microbial effector proteins that act either inside (cytoplasmic) or outside (apoplastic) the plant cells and modify the abundance or activity of host macromolecules. We compile novel insights into the much-disputed processes of effector secretion and translocation of filamentous organisms, namely fungi and oomycetes. We report how recent studies that focus on unconventional secretion and effector structure challenge the long-standing image of effectors as conventionally secreted proteins that are translocated with the aid of primary amino acid sequence motifs. Furthermore, we emphasize the potential of diverse, unbiased, state-of-the-art proteomics approaches in the holistic characterization of fungal and oomycete effectomes.
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Affiliation(s)
- Naomi Stuer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium
| | - Petra Van Damme
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Karel Lodewijk Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Sofie Goormachtig
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium.
| | - Judith Van Dingenen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052 Ghent, Belgium.
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3
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Lovelace AH, Dorhmi S, Hulin MT, Li Y, Mansfield JW, Ma W. Effector Identification in Plant Pathogens. PHYTOPATHOLOGY 2023; 113:637-650. [PMID: 37126080 DOI: 10.1094/phyto-09-22-0337-kd] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Effectors play a central role in determining the outcome of plant-pathogen interactions. As key virulence proteins, effectors are collectively indispensable for disease development. By understanding the virulence mechanisms of effectors, fundamental knowledge of microbial pathogenesis and disease resistance have been revealed. Effectors are also considered double-edged swords because some of them activate immunity in disease resistant plants after being recognized by specific immune receptors, which evolved to monitor pathogen presence or activity. Characterization of effector recognition by their cognate immune receptors and the downstream immune signaling pathways is instrumental in implementing resistance. Over the past decades, substantial research effort has focused on effector biology, especially concerning their interactions with virulence targets or immune receptors in plant cells. A foundation of this research is robust identification of the effector repertoire from a given pathogen, which depends heavily on bioinformatic prediction. In this review, we summarize methodologies that have been used for effector mining in various microbial pathogens which use different effector delivery mechanisms. We also discuss current limitations and provide perspectives on how recently developed analytic tools and technologies may facilitate effector identification and hence generation of a more complete vision of host-pathogen interactions. [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)
| | - Sara Dorhmi
- The Sainsbury Laboratory, Norwich, NR4 7UH, U.K
- Department of Microbiology and Plant Pathology, University of California Riverside, CA 92521, U.S.A
| | | | - Yufei Li
- The Sainsbury Laboratory, Norwich, NR4 7UH, U.K
| | - John W Mansfield
- Faculty of Natural Sciences, Imperial College London, London, SW7 2BX, U.K
| | - Wenbo Ma
- The Sainsbury Laboratory, Norwich, NR4 7UH, U.K
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4
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Oliveira-Garcia E, Tamang TM, Park J, Dalby M, Martin-Urdiroz M, Rodriguez Herrero C, Vu AH, Park S, Talbot NJ, Valent B. Clathrin-mediated endocytosis facilitates the internalization of Magnaporthe oryzae effectors into rice cells. THE PLANT CELL 2023:koad094. [PMID: 36976907 DOI: 10.1093/plcell/koad094] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 06/18/2023]
Abstract
Fungi and oomycetes deliver effectors into living plant cells to suppress defenses and control plant processes needed for infection. Little is known about the mechanism by which these pathogens translocate effector proteins across the plasma membrane into the plant cytoplasm. The blast fungus Magnaporthe oryzae secretes cytoplasmic effectors into a specialized biotrophic interfacial complex (BIC) before translocation. Here we show that cytoplasmic effectors within BICs are packaged into punctate membranous effector compartments that are occasionally observed in the host cytoplasm. Live cell imaging with fluorescently labeled proteins in rice (Oryza sativa) showed that these effector puncta colocalize with the plant plasma membrane and with CLATHRIN LIGHT CHAIN 1, a component of clathrin-mediated endocytosis (CME). Inhibiting CME using virus-induced gene silencing and chemical treatments resulted in cytoplasmic effectors in swollen BICs lacking effector puncta. By contrast, fluorescent marker co-localization, gene silencing and chemical inhibitor studies failed to support a major role for clathrin-independent endocytosis in effector translocation. Effector localization patterns indicated that cytoplasmic effector translocation occurs underneath appressoria before invasive hyphal growth. Taken together, this study provides evidence that cytoplasmic effector translocation is mediated by clathrin-mediated endocytosis in BICs and suggests a role for M. oryzae effectors in co-opting plant endocytosis.
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Affiliation(s)
- Ely Oliveira-Garcia
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA
| | - Tej Man Tamang
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
- Department of Horticulture and Natural Resources, Kansas State University, Manhattan, KS 66506, USA
| | - Jungeun Park
- Department of Horticulture and Natural Resources, Kansas State University, Manhattan, KS 66506, USA
| | - Melinda Dalby
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | | | - Clara Rodriguez Herrero
- School of Biosciences, University of Exeter, Exeter, EX4 4QD, UK
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich NR4 7UH, UK
| | - An Hong Vu
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA
| | - Sunghun Park
- Department of Horticulture and Natural Resources, Kansas State University, Manhattan, KS 66506, USA
| | - Nicholas J Talbot
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich NR4 7UH, UK
| | - Barbara Valent
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
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5
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Khan M, Djamei A. Co-immunoprecipitation-Based Identification of Effector-Host Protein Interactions from Pathogen-Infected Plant Tissue. Methods Mol Biol 2023; 2690:87-100. [PMID: 37450139 DOI: 10.1007/978-1-0716-3327-4_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
Protein-protein interactions play an essential role in host-pathogen interactions. Phytopathogens secrete a cocktail of effector proteins to suppress plant immunity and reprogram host cell metabolism in their favor. Identification and characterization of effectors and their target protein complexes by co-immunoprecipitation can help to gain a deeper understanding of the functions of individual effectors during pathogenicity and can also provide new insights into the wiring of plant signaling pathways or metabolic complexes. Here we describe a detailed protocol to perform co-immunoprecipitation of effector-target protein complexes from plant extracts with an example of the Ustilago maydis/maize pathosystem for which we also provide a fungal protoplast transformation and maize seedling infection protocols.
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Affiliation(s)
- Mamoona Khan
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany.
| | - Armin Djamei
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
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6
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Li GB, He JX, Wu JL, Wang H, Zhang X, Liu J, Hu XH, Zhu Y, Shen S, Bai YF, Yao ZL, Liu XX, Zhao JH, Li DQ, Li Y, Huang F, Huang YY, Zhao ZX, Zhang JW, Zhou SX, Ji YP, Pu M, Qin P, Li S, Chen X, Wang J, He M, Li W, Wu XJ, Xu ZJ, Wang WM, Fan J. Overproduction of OsRACK1A, an effector-targeted scaffold protein promoting OsRBOHB-mediated ROS production, confers rice floral resistance to false smut disease without yield penalty. MOLECULAR PLANT 2022; 15:1790-1806. [PMID: 36245122 DOI: 10.1016/j.molp.2022.10.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 09/14/2022] [Accepted: 10/14/2022] [Indexed: 06/16/2023]
Abstract
Grain formation is fundamental for crop yield but is vulnerable to abiotic and biotic stresses. Rice grain production is threatened by the false smut fungus Ustilaginoidea virens, which specifically infects rice floral organs, disrupting fertilization and seed formation. However, little is known about the molecular mechanisms of the U. virens-rice interaction and the genetic basis of floral resistance. Here, we report that U. virens secretes a cytoplasmic effector, UvCBP1, to facilitate infection of rice flowers. Mechanistically, UvCBP1 interacts with the rice scaffold protein OsRACK1A and competes its interaction with the reduced nicotinamide adenine dinucleotide phosphate oxidase OsRBOHB, leading to inhibition of reactive oxygen species (ROS) production. Although the analysis of natural variation revealed no OsRACK1A variants that could avoid being targeted by UvCBP1, expression levels of OsRACK1A are correlated with field resistance against U. virens in rice germplasm. Overproduction of OsRACK1A restores the OsRACK1A-OsRBOHB association and promotes OsRBOHB phosphorylation to enhance ROS production, conferring rice floral resistance to U. virens without yield penalty. Taken together, our findings reveal a new pathogenic mechanism mediated by an essential effector from a flower-specific pathogen and provide a valuable genetic resource for balancing disease resistance and crop yield.
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Affiliation(s)
- Guo-Bang Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China; Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Jia-Xue He
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Jin-Long Wu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - He Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Xin Zhang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Jie Liu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Xiao-Hong Hu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Yong Zhu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Shuai Shen
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Yi-Fei Bai
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Zong-Lin Yao
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Xin-Xian Liu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Jing-Hao Zhao
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - De-Qiang Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Yan Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Fu Huang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Yan-Yan Huang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Zhi-Xue Zhao
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Ji-Wei Zhang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Shi-Xin Zhou
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Yun-Peng Ji
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Mei Pu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Peng Qin
- Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Shigui Li
- Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Xuewei Chen
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Jing Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Min He
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China
| | - Weitao Li
- Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Xian-Jun Wu
- Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Zheng-Jun Xu
- Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Wen-Ming Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China.
| | - Jing Fan
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu 611130, China.
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7
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Bindics J, Khan M, Uhse S, Kogelmann B, Baggely L, Reumann D, Ingole KD, Stirnberg A, Rybecky A, Darino M, Navarrete F, Doehlemann G, Djamei A. Many ways to TOPLESS - manipulation of plant auxin signalling by a cluster of fungal effectors. THE NEW PHYTOLOGIST 2022; 236:1455-1470. [PMID: 35944559 DOI: 10.1111/nph.18315] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Plant biotrophic pathogens employ secreted molecules, called effectors, to suppress the host immune system and redirect the host's metabolism and development in their favour. Putative effectors of the gall-inducing maize pathogenic fungus Ustilago maydis were analysed for their ability to induce auxin signalling in plants. Using genetic, biochemical, cell-biological, and bioinformatic approaches we functionally elucidate a set of five, genetically linked effectors, called Topless (TPL) interacting protein (Tips) effectors that induce auxin signalling. We show that Tips induce auxin signalling by interfering with central corepressors of the TPL family. CRISPR-Cas9 mutants and deletion strain analysis indicate that the auxin signalling inducing subcluster effectors plays a redundant role in virulence. Although none of the Tips seem to have a conserved interaction motif, four of them bind solely to the N-terminal TPL domain and, for Tip1 and Tip4, we demonstrate direct competition with auxin/indole-3-acetic acid transcriptional repressors for their binding to TPL class of corepressors. Our findings reveal that TPL proteins, key regulators of growth-defence antagonism, are a major target of the U. maydis effectome.
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Affiliation(s)
- Janos Bindics
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Mamoona Khan
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Nussallee 9, 53115, Bonn, Germany
| | - Simon Uhse
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Benjamin Kogelmann
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Laura Baggely
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Daniel Reumann
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Kishor D Ingole
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Nussallee 9, 53115, Bonn, Germany
| | - Alexandra Stirnberg
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Anna Rybecky
- CEPLAS, Institute for Plant Sciences, University of Cologne, 50674, Cologne, Germany
| | - Martin Darino
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Fernando Navarrete
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Gunther Doehlemann
- CEPLAS, Institute for Plant Sciences, University of Cologne, 50674, Cologne, Germany
| | - Armin Djamei
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Nussallee 9, 53115, Bonn, Germany
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstraße 3, D-06466, Stadt Seeland, Germany
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8
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Kahmann R. My Personal Journey from the Fascination for Phages to a Tumor-Inducing Fungal Pathogen of Corn. Annu Rev Microbiol 2022; 76:1-19. [PMID: 35395169 DOI: 10.1146/annurev-micro-121721-111032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
My path in science began with a fascination for microbiology and phages and later involved a switch of subjects to the fungus Ustilago maydis and how it causes disease in maize. I will not provide a review of my work but rather focus on decisive findings, serendipitous, lucky moments when major advances made the U. maydis-maize system what it is now-a well-established model for biotrophic fungi. I also want to share with you the joy of finding the needle in a haystack at the very end of my scientific career, a fungal structure likely used for effector delivery, and how we were able to translate this into a potential application in agriculture. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Regine Kahmann
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany;
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9
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Navarrete F, Gallei M, Kornienko AE, Saado I, Khan M, Chia KS, Darino MA, Bindics J, Djamei A. TOPLESS promotes plant immunity by repressing auxin signaling and is targeted by the fungal effector Naked1. PLANT COMMUNICATIONS 2022; 3:100269. [PMID: 35529945 PMCID: PMC9073326 DOI: 10.1016/j.xplc.2021.100269] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 10/21/2021] [Accepted: 11/21/2021] [Indexed: 05/05/2023]
Abstract
In plants, the antagonism between growth and defense is hardwired by hormonal signaling. The perception of pathogen-associated molecular patterns (PAMPs) from invading microorganisms inhibits auxin signaling and plant growth. Conversely, pathogens manipulate auxin signaling to promote disease, but how this hormone inhibits immunity is not fully understood. Ustilago maydis is a maize pathogen that induces auxin signaling in its host. We characterized a U. maydis effector protein, Naked1 (Nkd1), that is translocated into the host nucleus. Through its native ethylene-responsive element binding factor-associated amphiphilic repression (EAR) motif, Nkd1 binds to the transcriptional co-repressors TOPLESS/TOPLESS-related (TPL/TPRs) and prevents the recruitment of a transcriptional repressor involved in hormonal signaling, leading to the de-repression of auxin and jasmonate signaling and thereby promoting susceptibility to (hemi)biotrophic pathogens. A moderate upregulation of auxin signaling inhibits the PAMP-triggered reactive oxygen species (ROS) burst, an early defense response. Thus, our findings establish a clear mechanism for auxin-induced pathogen susceptibility. Engineered Nkd1 variants with increased expression or increased EAR-mediated TPL/TPR binding trigger typical salicylic-acid-mediated defense reactions, leading to pathogen resistance. This implies that moderate binding of Nkd1 to TPL is a result of a balancing evolutionary selection process to enable TPL manipulation while avoiding host recognition.
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Affiliation(s)
- Fernando Navarrete
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Michelle Gallei
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Aleksandra E. Kornienko
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Indira Saado
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstraße 3, 06466 Stadt Seeland, Germany
| | - Mamoona Khan
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstraße 3, 06466 Stadt Seeland, Germany
| | - Khong-Sam Chia
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstraße 3, 06466 Stadt Seeland, Germany
| | - Martin A. Darino
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Janos Bindics
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Armin Djamei
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstraße 3, 06466 Stadt Seeland, Germany
- Corresponding author
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10
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Prediction of effector proteins and their implications in pathogenicity of phytopathogenic filamentous fungi: A review. Int J Biol Macromol 2022; 206:188-202. [PMID: 35227707 DOI: 10.1016/j.ijbiomac.2022.02.133] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/11/2022] [Accepted: 02/22/2022] [Indexed: 12/14/2022]
Abstract
Plant pathogenic fungi encode and secrete effector proteins to promote pathogenesis. In recent years, the important role of effector proteins in fungi and plant host interactions has become increasingly prominent. In this review, the functional characterization and molecular mechanisms by which fungal effector proteins modulate biological processes and suppress the defense of plant hosts are discussed, with an emphasis on cell localization during fungal infection. This paper also provides a comprehensive review of bioinformatic and experimental methods that are currently available for the identification of fungal effector proteins. We additionally summarize the secretion pathways and the methods for verifying the presence effector proteins in plant host cells. For future research, comparative genomic studies of different pathogens with varying life cycles will allow comprehensive and systematic identification of effector proteins. Additionally, functional analysis of effector protein interactions with a wider range of hosts (especially non-model crops) will provide more detailed repertoires of fungal effectors. Identifying effector proteins and verifying their functions will improve our understanding of their role in causing disease and in turn guide future strategies for combatting fungal infections.
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Kanja C, Hammond‐Kosack KE. Proteinaceous effector discovery and characterization in filamentous plant pathogens. MOLECULAR PLANT PATHOLOGY 2020; 21:1353-1376. [PMID: 32767620 PMCID: PMC7488470 DOI: 10.1111/mpp.12980] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 06/03/2020] [Accepted: 07/05/2020] [Indexed: 05/26/2023]
Abstract
The complicated interplay of plant-pathogen interactions occurs on multiple levels as pathogens evolve to constantly evade the immune responses of their hosts. Many economically important crops fall victim to filamentous pathogens that produce small proteins called effectors to manipulate the host and aid infection/colonization. Understanding the effector repertoires of pathogens is facilitating an increased understanding of the molecular mechanisms underlying virulence as well as guiding the development of disease control strategies. The purpose of this review is to give a chronological perspective on the evolution of the methodologies used in effector discovery from physical isolation and in silico predictions, to functional characterization of the effectors of filamentous plant pathogens and identification of their host targets.
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Affiliation(s)
- Claire Kanja
- Department of Biointeractions and Crop ProtectionRothamsted ResearchHarpendenUK
- School of BiosciencesUniversity of NottinghamNottinghamUK
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Tintor N, Paauw M, Rep M, Takken FLW. The root-invading pathogen Fusarium oxysporum targets pattern-triggered immunity using both cytoplasmic and apoplastic effectors. THE NEW PHYTOLOGIST 2020; 227:1479-1492. [PMID: 32323328 PMCID: PMC7496899 DOI: 10.1111/nph.16618] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 04/09/2020] [Indexed: 05/08/2023]
Abstract
Plant pathogens use effector proteins to promote host colonisation. The mode of action of effectors from root-invading pathogens, such as Fusarium oxysporum (Fo), is poorly understood. Here, we investigated whether Fo effectors suppress pattern-triggered immunity (PTI), and whether they enter host cells during infection. Eight candidate effectors of an Arabidopsis-infecting Fo strain were expressed with and without signal peptide for secretion in Nicotiana benthamiana and their effect on flg22-triggered and chitin-triggered reactive oxidative species (ROS) burst was monitored. To detect uptake, effector biotinylation by an intracellular Arabidopsis-produced biotin ligase was examined following root infection. Four effectors suppressed PTI signalling; two acted intracellularly and two apoplastically. Heterologous expression of a PTI-suppressing effector in Arabidopsis enhanced bacterial susceptibility. Consistent with an intracellular activity, host cell uptake of five effectors, but not of the apoplastically acting ones, was detected in Fo-infected Arabidopsis roots. Multiple Fo effectors targeted PTI signalling, uncovering a surprising overlap in infection strategies between foliar and root pathogens. Extracellular targeting of flg22 signalling by a microbial effector provides a new mechanism on how plant pathogens manipulate their host. Effector translocation appears independent of protein size, charge, presence of conserved motifs or the promoter driving its expression.
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Affiliation(s)
- Nico Tintor
- Molecular Plant PathologySILSUniversity of AmsterdamPO Box 942151090 GEAmsterdamthe Netherlands
| | - Misha Paauw
- Molecular Plant PathologySILSUniversity of AmsterdamPO Box 942151090 GEAmsterdamthe Netherlands
| | - Martijn Rep
- Molecular Plant PathologySILSUniversity of AmsterdamPO Box 942151090 GEAmsterdamthe Netherlands
| | - Frank L. W. Takken
- Molecular Plant PathologySILSUniversity of AmsterdamPO Box 942151090 GEAmsterdamthe Netherlands
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Youssar L, Wernet V, Hensel N, Yu X, Hildebrand HG, Schreckenberger B, Kriegler M, Hetzer B, Frankino P, Dillin A, Fischer R. Intercellular communication is required for trap formation in the nematode-trapping fungus Duddingtonia flagrans. PLoS Genet 2019; 15:e1008029. [PMID: 30917129 PMCID: PMC6453484 DOI: 10.1371/journal.pgen.1008029] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 04/08/2019] [Accepted: 02/18/2019] [Indexed: 11/21/2022] Open
Abstract
Nematode-trapping fungi (NTF) are a large and diverse group of fungi, which may switch from a saprotrophic to a predatory lifestyle if nematodes are present. Different fungi have developed different trapping devices, ranging from adhesive cells to constricting rings. After trapping, fungal hyphae penetrate the worm, secrete lytic enzymes and form a hyphal network inside the body. We sequenced the genome of Duddingtonia flagrans, a biotechnologically important NTF used to control nematode populations in fields. The 36.64 Mb genome encodes 9,927 putative proteins, among which are more than 638 predicted secreted proteins. Most secreted proteins are lytic enzymes, but more than 200 were classified as small secreted proteins (< 300 amino acids). 117 putative effector proteins were predicted, suggesting interkingdom communication during the colonization. As a first step to analyze the function of such proteins or other phenomena at the molecular level, we developed a transformation system, established the fluorescent proteins GFP and mCherry, adapted an assay to monitor protein secretion, and established gene-deletion protocols using homologous recombination or CRISPR/Cas9. One putative virulence effector protein, PefB, was transcriptionally induced during the interaction. We show that the mature protein is able to be imported into nuclei in Caenorhabditis elegans cells. In addition, we studied trap formation and show that cell-to-cell communication is required for ring closure. The availability of the genome sequence and the establishment of many molecular tools will open new avenues to studying this biotechnologically relevant nematode-trapping fungus. Nematode-trapping fungi are fascinating microorganisms, because they are able to switch from saprotrophic growth to a predatory lifestyle. Duddingtonia flagrans forms adhesive trap systems and conidia and resistant chlamydospores. Chlamydospores are ideal for dissemination in the environment to control nematode populations in the field. We show that D. flagrans is able to catch C. elegans but also the very large wine-pathogenic nematode Xiphinema index. We sequenced the D. flagrans genome and show that it encodes about 10,000 genes with a large proportion of secreted proteins. We hypothesize that virulence effector proteins are involved in the interkingdom organismic interaction and identified more than 100 candidates. In order to investigate the molecular biology of D. flagrans and its interaction with nematodes, we established a transformation system and several molecular tools. We show that cell-to-cell communication and hyphal fusion are required for trap formation. Finally, we show that one putative virulence effector protein targets nuclei when expressed in C. elegans.
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Affiliation(s)
- Loubna Youssar
- Department of Microbiology, Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
| | - Valentin Wernet
- Department of Microbiology, Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
| | - Nicole Hensel
- Department of Microbiology, Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
| | - Xi Yu
- Department of Microbiology, Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
| | - Heinz-Georg Hildebrand
- Department of Microbiology, Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
| | - Birgit Schreckenberger
- Department of Microbiology, Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
| | - Marius Kriegler
- Department of Microbiology, Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
| | | | - Phillip Frankino
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of Berkeley, Berkeley, California, United States of America
| | - Andrew Dillin
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of Berkeley, Berkeley, California, United States of America
| | - Reinhard Fischer
- Department of Microbiology, Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
- * E-mail:
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Roth R, Hillmer S, Funaya C, Chiapello M, Schumacher K, Lo Presti L, Kahmann R, Paszkowski U. Arbuscular cell invasion coincides with extracellular vesicles and membrane tubules. NATURE PLANTS 2019; 5:204-211. [PMID: 30737514 DOI: 10.1038/s41477-019-0365-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 01/08/2019] [Indexed: 05/08/2023]
Abstract
During establishment of arbuscular mycorrhizal symbioses, fungal hyphae invade root cells producing transient tree-like structures, the arbuscules, where exchange of photosynthates for soil minerals occurs. Arbuscule formation and collapse lead to rapid production and degradation of plant and fungal membranes, their spatiotemporal dynamics directly influencing nutrient exchange. We determined the ultra-structural details of both membrane surfaces and the interstitial apoplastic matrix by transmission electron microscopy tomography during growth and senescence of Rhizophagus irregularis arbuscules in rice. Invasive growth of arbuscular hyphae was associated with abundant fungal membrane tubules (memtubs) and plant peri-arbuscular membrane evaginations. Similarly, the phylogenetically distant arbuscular mycorrhizal fungus, Gigaspora rosea, and the fungal maize pathogen, Ustilago maydis, developed memtubs while invading host cells, revealing structural commonalities independent of the mutualistic or parasitic outcome of the interaction. Additionally, extracellular vesicles formed continuously in the peri-arbuscular interface from arbuscule biogenesis to senescence, suggesting an involvement in inter-organismic signal and nutrient exchange throughout the arbuscule lifespan.
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Affiliation(s)
- Ronelle Roth
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Stefan Hillmer
- Electron Microscopy Core Facility, University of Heidelberg, Heidelberg, Germany
| | - Charlotta Funaya
- Electron Microscopy Core Facility, University of Heidelberg, Heidelberg, Germany
| | - Marco Chiapello
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Karin Schumacher
- Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Libera Lo Presti
- Max-Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Springer Nature Heidelberg, Berlin, Germany
| | - Regine Kahmann
- Max-Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Uta Paszkowski
- Department of Plant Sciences, University of Cambridge, Cambridge, UK.
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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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Ma LS, Wang L, Trippel C, Mendoza-Mendoza A, Ullmann S, Moretti M, Carsten A, Kahnt J, Reissmann S, Zechmann B, Bange G, Kahmann R. The Ustilago maydis repetitive effector Rsp3 blocks the antifungal activity of mannose-binding maize proteins. Nat Commun 2018; 9:1711. [PMID: 29703884 PMCID: PMC5923269 DOI: 10.1038/s41467-018-04149-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 04/06/2018] [Indexed: 12/22/2022] Open
Abstract
To cause disease in maize, the biotrophic fungus Ustilago maydis secretes a large arsenal of effector proteins. Here, we functionally characterize the repetitive effector Rsp3 (repetitive secreted protein 3), which shows length polymorphisms in field isolates and is highly expressed during biotrophic stages. Rsp3 is required for virulence and anthocyanin accumulation. During biotrophic growth, Rsp3 decorates the hyphal surface and interacts with at least two secreted maize DUF26-domain family proteins (designated AFP1 and AFP2). AFP1 binds mannose and displays antifungal activity against the rsp3 mutant but not against a strain constitutively expressing rsp3. Maize plants silenced for AFP1 and AFP2 partially rescue the virulence defect of rsp3 mutants, suggesting that blocking the antifungal activity of AFP1 and AFP2 by the Rsp3 effector is an important virulence function. Rsp3 orthologs are present in all sequenced smut fungi, and the ortholog from Sporisorium reilianum can complement the rsp3 mutant of U. maydis, suggesting a novel widespread fungal protection mechanism. The fungus Ustilago maydis secretes many effector proteins to cause disease in maize. Here, Ma et al. show that the repetitive effector Rsp3 is required for virulence by inhibiting the antifungal activity of two mannose-binding proteins that are secreted by the plant cells.
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Affiliation(s)
- Lay-Sun Ma
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Lei Wang
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.,Department of Pharmacology, Max Planck Institute for Heart and Lung Research, 61231, Bad Nauheim, Germany
| | - Christine Trippel
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.,Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University-Göttingen, 37077, Göttingen, Germany
| | - Artemio Mendoza-Mendoza
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.,Bio-Protection Research Centre, Lincoln University, PO Box 64, Lincoln, 7647, New Zealand
| | - Steffen Ullmann
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.,, Düsseldorfer Straße 177, 45481, Mülheim an der Ruhr, Germany
| | - Marino Moretti
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Alexander Carsten
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Jörg Kahnt
- Mass Spectroscopy Facility, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Stefanie Reissmann
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Bernd Zechmann
- Center for Microscopy and Imaging (CMI), Baylor University, Waco, Texas, 76798-7046, USA
| | - Gert Bange
- LOEWE Center for Synthetic Microbiology and Faculty of Chemistry, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Regine Kahmann
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.
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Dalio RJD, Herlihy J, Oliveira TS, McDowell JM, Machado M. Effector Biology in Focus: A Primer for Computational Prediction and Functional Characterization. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:22-33. [PMID: 29023190 DOI: 10.1094/mpmi-07-17-0174-fi] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plant-pathogen interactions are controlled by a multilayered immune system, which is activated by pathogen recognition in the host. Pathogens secrete effector molecules to interfere with the immune recognition or signaling network and reprogram cell structure or metabolism. Understanding the effector repertoires of diverse pathogens will contribute to unraveling the molecular mechanism of virulence and developing sustainable disease-control strategies for crops and natural ecosystems. Effector functionality has been investigated extensively in only a small number of pathogen species. However, many more pathogen genomes are becoming available, and much can be learned from a broader view of effector biology in diverse pathosystems. The purpose of this review is to summarize methodology for computational prediction of protein effectors, functional characterization of effector proteins and their targets, and the use of effectors as probes to screen for new sources of host resistance. Although these techniques were generally developed in model pathosystems, many of the approaches are directly applicable for exploration and exploitation of effector biology in pathosystems that are less well studied. We hope to facilitate such exploration, which will broaden understanding of the mechanisms that underpin the biological diversity of plant-pathogen interactions, and maximize the impact of new approaches that leverage effector biology for disease control.
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Affiliation(s)
- Ronaldo J D Dalio
- 1 Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IA, Cordeirópolis-SP, Brazil; and
| | - John Herlihy
- 2 Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA, 24061-0329, U.S.A
| | - Tiago S Oliveira
- 1 Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IA, Cordeirópolis-SP, Brazil; and
| | - John M McDowell
- 2 Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA, 24061-0329, U.S.A
| | - Marcos Machado
- 1 Citrus Biotechnology Lab, Centro de Citricultura Sylvio Moreira, IA, Cordeirópolis-SP, Brazil; and
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Lo Presti L, Kahmann R. How filamentous plant pathogen effectors are translocated to host cells. CURRENT OPINION IN PLANT BIOLOGY 2017; 38:19-24. [PMID: 28460240 DOI: 10.1016/j.pbi.2017.04.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/05/2017] [Accepted: 04/10/2017] [Indexed: 06/07/2023]
Abstract
The interaction of microbes with "signature" plants is largely governed by secreted effector proteins, which serve to dampen plant defense responses and modulate host cell processes. Secreted effectors can function either in the apoplast or within plant cell compartments. How oomycetes and fungi translocate their effectors to plant cells is still poorly understood and controversial. While most oomycete effectors share a common 'signature' that was proposed to mediate their uptake via endocytosis, fungal effectors display no conserved motifs at the primary amino acid sequence level. Here we summarize current knowledge in the field of oomycete and fungal effector uptake and highlight emerging themes that may unite rather than set apart these unrelated filamentous pathogens.
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Affiliation(s)
- Libera Lo Presti
- Max Planck Institute for Terrestrial Microbiology, Dept. Organismic Interactions, Karl-von-Frisch-Strasse 10, 35043 Marburg, Germany
| | - Regine Kahmann
- Max Planck Institute for Terrestrial Microbiology, Dept. Organismic Interactions, Karl-von-Frisch-Strasse 10, 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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Oeser B, Kind S, Schurack S, Schmutzer T, Tudzynski P, Hinsch J. Cross-talk of the biotrophic pathogen Claviceps purpurea and its host Secale cereale. BMC Genomics 2017; 18:273. [PMID: 28372538 PMCID: PMC5379732 DOI: 10.1186/s12864-017-3619-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/10/2017] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The economically important Ergot fungus Claviceps purpurea is an interesting biotrophic model system because of its strict organ specificity (grass ovaries) and the lack of any detectable plant defense reactions. Though several virulence factors were identified, the exact infection mechanisms are unknown, e.g. how the fungus masks its attack and if the host detects the infection at all. RESULTS We present a first dual transcriptome analysis using an RNA-Seq approach. We studied both, fungal and plant gene expression in young ovaries infected by the wild-type and two virulence-attenuated mutants. We can show that the plant recognizes the fungus, since defense related genes are upregulated, especially several phytohormone genes. We present a survey of in planta expressed fungal genes, among them several confirmed virulence genes. Interestingly, the set of most highly expressed genes includes a high proportion of genes encoding putative effectors, small secreted proteins which might be involved in masking the fungal attack or interfering with host defense reactions. As known from several other phytopathogens, the C. purpurea genome contains more than 400 of such genes, many of them clustered and probably highly redundant. Since the lack of effective defense reactions in spite of recognition of the fungus could very well be achieved by effectors, we started a functional analysis of some of the most highly expressed candidates. However, the redundancy of the system made the identification of a drastic effect of a single gene most unlikely. We can show that at least one candidate accumulates in the plant apoplast. Deletion of some candidates led to a reduced virulence of C. purpurea on rye, indicating a role of the respective proteins during the infection process. CONCLUSIONS We show for the first time that- despite the absence of effective plant defense reactions- the biotrophic pathogen C. purpurea is detected by its host. This points to a role of effectors in modulation of the effective plant response. Indeed, several putative effector genes are among the highest expressed genes in planta.
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Affiliation(s)
- Birgitt Oeser
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D-48143 Münster, Germany
| | - Sabine Kind
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D-48143 Münster, Germany
| | - Selma Schurack
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D-48143 Münster, Germany
| | - Thomas Schmutzer
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Paul Tudzynski
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D-48143 Münster, Germany
| | - Janine Hinsch
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D-48143 Münster, Germany
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