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Khan M, Uhse S, Bindics J, Kogelmann B, Nagarajan N, Tabassum R, Ingole KD, Djamei A. Tip of the iceberg? Three novel TOPLESS-interacting effectors of the gall-inducing fungus Ustilago maydis. THE NEW PHYTOLOGIST 2024. [PMID: 39021059 DOI: 10.1111/nph.19967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 06/24/2024] [Indexed: 07/20/2024]
Abstract
Ustilago maydis is a biotrophic pathogen causing smut disease in maize. It secretes a cocktail of effector proteins, which target different host proteins during its biotrophic stages in the host plant. One such class of proteins we identified previously is TOPLESS (TPL) and TOPLESS-RELATED (TPR) transcriptional corepressors. Here, we screened 297 U. maydis effector candidates for their ability to interact with maize TPL protein RAMOSA 1 ENHANCER LOCUS 2 LIKE 2 (RELK2) and their ability to induce auxin signaling and thereby identified three novel TPL-interacting protein effectors (Tip6, Tip7, and Tip8). Structural modeling and mutational analysis allowed the identification of TPL-interaction motifs of Tip6 and Tip7. In planta interaction between Tip6 and Tip7 with RELK2 occurs mainly in nuclear compartments, whereas Tip8 colocalizes with RELK2 in a compartment outside the nucleus. Overexpression of Tip8 in nonhost plants leads to cell death, indicating recognition of the effector or its activity. By performing infection assays with single and multideletion mutants of U. maydis, we demonstrate a positive role of Tip6 and Tip7 in U. maydis virulence. Transcriptional profiling of maize leaves infected with Tip effector mutants in comparison with SG200 strain suggests Tip effector activities are not merely redundant.
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Affiliation(s)
- Mamoona Khan
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Nussallee 9, Bonn, 53115, Germany
| | - Simon Uhse
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, Vienna, 1030, Austria
| | - Janos Bindics
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, Vienna, 1030, Austria
| | - Benjamin Kogelmann
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, Vienna, 1030, Austria
| | - Nithya Nagarajan
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Nussallee 9, Bonn, 53115, Germany
| | - Riaz Tabassum
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Nussallee 9, Bonn, 53115, Germany
| | - Kishor D Ingole
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Nussallee 9, Bonn, 53115, Germany
| | - Armin Djamei
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Nussallee 9, Bonn, 53115, Germany
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences (OEAW), Vienna Bio Center (VBC), Dr. Bohr-Gasse 3, Vienna, 1030, Austria
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2
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Schuster M, Schweizer G, Reißmann S, Happel P, Aßmann D, Rössel N, Güldener U, Mannhaupt G, Ludwig N, Winterberg S, Pellegrin C, Tanaka S, Vincon V, Presti LL, Wang L, Bender L, Gonzalez C, Vranes M, Kämper J, Seong K, Krasileva K, Kahmann R. Novel Secreted Effectors Conserved Among Smut Fungi Contribute to the Virulence of Ustilago maydis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:250-263. [PMID: 38416124 DOI: 10.1094/mpmi-09-23-0139-fi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Fungal pathogens deploy a set of molecules (proteins, specialized metabolites, and sRNAs), so-called effectors, to aid the infection process. In comparison to other plant pathogens, smut fungi have small genomes and secretomes of 20 Mb and around 500 proteins, respectively. Previous comparative genomic studies have shown that many secreted effector proteins without known domains, i.e., novel, are conserved only in the Ustilaginaceae family. By analyzing the secretomes of 11 species within Ustilaginaceae, we identified 53 core homologous groups commonly present in this lineage. By collecting existing mutants and generating additional ones, we gathered 44 Ustilago maydis strains lacking single core effectors as well as 9 strains containing multiple deletions of core effector gene families. Pathogenicity assays revealed that 20 of these 53 mutant strains were affected in virulence. Among the 33 mutants that had no obvious phenotypic changes, 13 carried additional, sequence-divergent, structurally similar paralogs. We report a virulence contribution of seven previously uncharacterized single core effectors and of one effector family. Our results help to prioritize effectors for understanding U. maydis virulence and provide genetic resources for further characterization. [Formula: see text] Copyright © 2024 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)
- Mariana Schuster
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle, Germany
| | - Gabriel Schweizer
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- Independent Data Lab UG, 80937 Munich, Germany
| | - Stefanie Reißmann
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Petra Happel
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Daniela Aßmann
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Nicole Rössel
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Ulrich Güldener
- Deutsches Herzzentrum München, Technische Universität München, 80636 München, Germany
| | - Gertrud Mannhaupt
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Nicole Ludwig
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- Research & Development, Weed Control Bayer AG, Crop Science Division, 65926 Frankfurt am Main, Germany
| | - Sarah Winterberg
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Clément Pellegrin
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Shigeyuki Tanaka
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Volker Vincon
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Libera Lo Presti
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Lei Wang
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Lena Bender
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- Department of Pharmaceutics and Biopharmaceutics, Phillips-University Marburg, 35037 Marburg, Germany
| | - Carla Gonzalez
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Miroslav Vranes
- Karlsruhe Institute of Technology, Institute for Applied Biosciences, Department of Genetics, 76131 Karlsruhe, Germany
| | - Jörg Kämper
- Karlsruhe Institute of Technology, Institute for Applied Biosciences, Department of Genetics, 76131 Karlsruhe, Germany
| | - Kyungyong Seong
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, U.S.A
| | - Ksenia Krasileva
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, U.S.A
| | - Regine Kahmann
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
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Huang L, Ökmen B, Stolze SC, Kastl M, Khan M, Hilbig D, Nakagami H, Djamei A, Doehlemann G. The fungal pathogen Ustilago maydis targets the maize corepressor RELK2 to modulate host transcription for tumorigenesis. THE NEW PHYTOLOGIST 2024; 241:1747-1762. [PMID: 38037456 DOI: 10.1111/nph.19448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 11/08/2023] [Indexed: 12/02/2023]
Abstract
Ustilago maydis is a biotrophic fungus that causes tumor formation on all aerial parts of maize. U. maydis secretes effector proteins during penetration and colonization to successfully overcome the plant immune response and reprogram host physiology to promote infection. In this study, we functionally characterized the U. maydis effector protein Topless (TPL) interacting protein 6 (Tip6). We found that Tip6 interacts with the N-terminus of RELK2 through its two Ethylene-responsive element binding factor-associated amphiphilic repression (EAR) motifs. We show that the EAR motifs are essential for the virulence function of Tip6 and critical for altering the nuclear distribution pattern of RELK2. We propose that Tip6 mimics the recruitment of RELK2 by plant repressor proteins, thus disrupting host transcriptional regulation. We show that a large group of AP2/ERF B1 subfamily transcription factors are misregulated in the presence of Tip6. Our study suggests a regulatory mechanism where the U. maydis effector Tip6 utilizes repressive domains to recruit the corepressor RELK2 to disrupt the transcriptional networks of the host plant.
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Affiliation(s)
- Luyao Huang
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, 50674, Germany
| | - Bilal Ökmen
- Department of Microbial Interactions, IMIT/ZMBP, University of Tübingen, Tübingen, 72076, Germany
| | - Sara Christina Stolze
- Protein Mass Spectrometry, Max-Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
| | - Melanie Kastl
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, 50674, Germany
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Bonn, 53127, Germany
| | - Mamoona Khan
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, 53115, Germany
| | - Daniel Hilbig
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, 50674, Germany
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Bonn, 53127, Germany
| | - Hirofumi Nakagami
- Protein Mass Spectrometry, Max-Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Basic Immune System of Plants, Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
| | - Armin Djamei
- Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, 53115, Germany
| | - Gunther Doehlemann
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, 50674, Germany
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Ökmen B, Katzy P, Huang L, Wemhöner R, Doehlemann G. A conserved extracellular Ribo1 with broad-spectrum cytotoxic activity enables smut fungi to compete with host-associated bacteria. THE NEW PHYTOLOGIST 2023; 240:1976-1989. [PMID: 37680042 DOI: 10.1111/nph.19244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 08/14/2023] [Indexed: 09/09/2023]
Abstract
Ribotoxins are secreted ribonucleases that specifically target and cleave the universally conserved sarcin-ricin loop sequence of rRNA, which leads to inhibition of protein biosynthesis and subsequently to cell death. We have identified and characterized a secreted Ribo1 protein of plant pathogenic smut fungi. Heterologous expression in different model systems showed that smut Ribo1 has cytotoxic activity against bacteria, yeast, host and nonhost plants. Recombinant expression of Ribo1 in Nicotiana benthamiana induced plant cell death; however, an active site mutant induced cell death only when expressed as a secreted protein. In the maize smut Ustilago maydis, transcription of Ribo1 is specifically induced in early infection stages. While a knockout mutant revealed that Ribo1 is dispensable for U. maydis virulence, the overexpression of Ribo1 in planta had a strong dominant negative effect on virulence and induced host defense responses including cell death. Our findings suggest a function of Ribo1 during the epiphytic development rather than for invasive colonization of the host. Accordingly, in the presence of the biocontrol bacteria Pantoea sp., which were isolated from maize leaves, the ribo1 knockout mutant was significantly impaired in virulence. Together, we conclude that Ribo1 enables smut fungi to compete with host-associated bacteria during epiphytic development.
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Affiliation(s)
- Bilal Ökmen
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Center for Molecular Biosciences, 50674, Cologne, Germany
- Department of Microbial Interactions, IMIT/ZMBP, University of Tübingen, 72076, Tübingen, Germany
| | - Philipp Katzy
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Center for Molecular Biosciences, 50674, Cologne, Germany
| | - Luyao Huang
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Center for Molecular Biosciences, 50674, Cologne, Germany
| | - Raphael Wemhöner
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Center for Molecular Biosciences, 50674, Cologne, Germany
| | - Gunther Doehlemann
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Center for Molecular Biosciences, 50674, Cologne, Germany
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5
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Zuo W, Depotter JRL, Stolze SC, Nakagami H, Doehlemann G. A transcriptional activator effector of Ustilago maydis regulates hyperplasia in maize during pathogen-induced tumor formation. Nat Commun 2023; 14:6722. [PMID: 37872143 PMCID: PMC10593772 DOI: 10.1038/s41467-023-42522-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 10/13/2023] [Indexed: 10/25/2023] Open
Abstract
Ustilago maydis causes common smut in maize, which is characterized by tumor formation in aerial parts of maize. Tumors result from the de novo cell division of highly developed bundle sheath and subsequent cell enlargement. However, the molecular mechanisms underlying tumorigenesis are still largely unknown. Here, we characterize the U. maydis effector Sts2 (Small tumor on seedlings 2), which promotes the division of hyperplasia tumor cells. Upon infection, Sts2 is translocated into the maize cell nucleus, where it acts as a transcriptional activator, and the transactivation activity is crucial for its virulence function. Sts2 interacts with ZmNECAP1, a yet undescribed plant transcriptional activator, and it activates the expression of several leaf developmental regulators to potentiate tumor formation. On the contrary, fusion of a suppressive SRDX-motif to Sts2 causes dominant negative inhibition of tumor formation, underpinning the central role of Sts2 for tumorigenesis. Our results not only disclose the virulence mechanism of a tumorigenic effector, but also reveal the essential role of leaf developmental regulators in pathogen-induced tumor formation.
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Affiliation(s)
- Weiliang Zuo
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, 50674, Germany.
| | - Jasper R L Depotter
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, 50674, Germany
- Bioinformatics and Biostatistics, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Sara Christina Stolze
- Protein Mass Spectrometry, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Hirofumi Nakagami
- Protein Mass Spectrometry, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
- Basic Immune System of Plants, Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
| | - Gunther Doehlemann
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, 50674, Germany.
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6
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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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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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Wilson RA, McDowell JM. Recent advances in understanding of fungal and oomycete effectors. CURRENT OPINION IN PLANT BIOLOGY 2022; 68:102228. [PMID: 35605341 DOI: 10.1016/j.pbi.2022.102228] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 06/15/2023]
Abstract
Fungal and oomycete pathogens secrete complex arrays of proteins and small RNAs to interface with plant-host targets and manipulate plant regulatory networks to the microbes' advantage. Research on these important virulence factors has been accelerated by improved genome sequences, refined bioinformatic prediction tools, and exploitation of efficient platforms for understanding effector gene expression and function. Recent studies have validated the expectation that oomycetes and fungi target many of the same sectors in immune signaling networks, but the specific host plant targets and modes of action are diverse. Effector research has also contributed to deeper understanding of the mechanisms of effector-triggered immunity.
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Affiliation(s)
- Richard A Wilson
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - John M McDowell
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA.
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9
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Ali M, Ahmad H, Amin B, Atif MJ, Cheng Z. Induce defense response of DADS in eggplants during the biotrophic phase of Verticillium dahliae. BMC PLANT BIOLOGY 2022; 22:172. [PMID: 35379184 PMCID: PMC8981950 DOI: 10.1186/s12870-022-03527-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 03/08/2022] [Indexed: 06/14/2023]
Abstract
PURPOSE Verticillium wilt is a destructive vascular disease in eggplants. The complex defensive mechanisms of eggplant against this disease are very limited. METHODS Our work examined the bioactive properties of garlic allelochemical diallyl disulfide (DADS) as potential biostimulants for defense against V. dahliae in eggplant seedlings. We, therefore, foliar sprayed DADS on eggplants to study the defense response during the early biotrophic phase of V. dahliae (a hemibiotroph). RESULTS DADS application significantly increased root peroxidase (POD), phenylalanine-ammonia lyase (PAL) enzyme activity, and reduced H2O2 levels after 24 h of fungal inoculation. Salicylic acid (SA) in leaves and roots was significantly increased while, the jasmonic acid (JA), indole acetic acid (IAA), and abscisic acid (ABA) levels were decreased. The microscopic examinations of V. dahliae infection in roots displayed that the progression of infection was restricted in DADS-treated plants. Depositions of lignin and phenolic compounds such as ferulic acid, p-coumaric acid, and caffeic acid content were significantly higher in DADS-treated plants at 48 h post-inoculation. Similarly, the DADS application up-regulated pathogenesis-related (PR1, PR2, and PR5), mitogen-activated protein kinase (MPK1), and lipoxygenase (LOX) genes. Furthermore, DADS-treated plants exhibited a lower disease severity index (23.3% vs. 57.0% in controls), indicating successful defense against V. dahliae. CONCLUSIONS Our findings concluded that the biological function of garlic allelochemical DADS has a prominent role in the higher defense resistance of eggplants during the early infection of V. dahliae.
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Affiliation(s)
- Muhammad Ali
- Department of Vegetable Science, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Husain Ahmad
- Department of Vegetable Science, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Bakht Amin
- Department of Vegetable Science, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Muhammad Jawaad Atif
- Department of Vegetable Science, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Zhihui Cheng
- Department of Vegetable Science, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.
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10
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Bosch J, Djamei A. Isolation of Ustilago bromivora Strains from Infected Spikelets through Spore Recovery and Germination. Bio Protoc 2017; 7:e2392. [PMID: 28781989 PMCID: PMC5540166 DOI: 10.21769/bioprotoc.2392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/09/2017] [Accepted: 06/13/2017] [Indexed: 11/02/2022] Open
Abstract
Ustilago bromivora is a biotrophic smut fungus infecting Brachypodium sp. It is closely related to the barley-infecting smut Ustilago hordei, and related to the well-studied, gall-inducing model pathogen Ustilago maydis. Upon flowering, the spikelets of U. bromivora-infected plants are filled with black fungal spores. While it is possible to directly use this spore material to infect Brachypodium seeds, in many cases it is more useful to isolate individual strains of U. bromivora for a genetically homogenous population. This protocol describes how to collect and germinate the spores of U. bromivora on plate in order to obtain strains derived from a single cell.
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Affiliation(s)
- Jason Bosch
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Armin Djamei
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
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