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Kusch S, Qian J, Loos A, Kümmel F, Spanu PD, Panstruga R. Long-term and rapid evolution in powdery mildew fungi. Mol Ecol 2024; 33:e16909. [PMID: 36862075 DOI: 10.1111/mec.16909] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 02/06/2023] [Accepted: 02/20/2023] [Indexed: 03/03/2023]
Abstract
The powdery mildew fungi (Erysiphaceae) are globally distributed plant pathogens with a range of more than 10,000 plant hosts. In this review, we discuss the long- and short-term evolution of these obligate biotrophic fungi and outline their diversity with respect to morphology, lifestyle, and host range. We highlight their remarkable ability to rapidly overcome plant immunity, evolve fungicide resistance, and broaden their host range, for example, through adaptation and hybridization. Recent advances in genomics and proteomics, particularly in cereal powdery mildews (genus Blumeria), provided first insights into mechanisms of genomic adaptation in these fungi. Transposable elements play key roles in shaping their genomes, where even close relatives exhibit diversified patterns of recent and ongoing transposon activity. These transposons are ubiquitously distributed in the powdery mildew genomes, resulting in a highly adaptive genome architecture lacking obvious regions of conserved gene space. Transposons can also be neofunctionalized to encode novel virulence factors, particularly candidate secreted effector proteins, which may undermine the plant immune system. In cereals like barley and wheat, some of these effectors are recognized by plant immune receptors encoded by resistance genes with numerous allelic variants. These effectors determine incompatibility ("avirulence") and evolve rapidly through sequence diversification and copy number variation. Altogether, powdery mildew fungi possess plastic genomes that enable their fast evolutionary adaptation towards overcoming plant immunity, host barriers, and chemical stress such as fungicides, foreshadowing future outbreaks, host range shifts and expansions as well as potential pandemics by these pathogens.
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Affiliation(s)
- Stefan Kusch
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Aachen, Germany
| | - Jiangzhao Qian
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Aachen, Germany
| | - Anne Loos
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Aachen, Germany
| | - Florian Kümmel
- Department of Plant-Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Pietro D Spanu
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Aachen, Germany
- Imperial College, London, UK
| | - Ralph Panstruga
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Aachen, Germany
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2
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Li Z, Velásquez‐Zapata V, Elmore JM, Li X, Xie W, Deb S, Tian X, Banerjee S, Jørgensen HJL, Pedersen C, Wise RP, Thordal‐Christensen H. Powdery mildew effectors AVR A1 and BEC1016 target the ER J-domain protein HvERdj3B required for immunity in barley. MOLECULAR PLANT PATHOLOGY 2024; 25:e13463. [PMID: 38695677 PMCID: PMC11064805 DOI: 10.1111/mpp.13463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/06/2024] [Accepted: 04/11/2024] [Indexed: 05/05/2024]
Abstract
The barley powdery mildew fungus, Blumeria hordei (Bh), secretes hundreds of candidate secreted effector proteins (CSEPs) to facilitate pathogen infection and colonization. One of these, CSEP0008, is directly recognized by the barley nucleotide-binding leucine-rich-repeat (NLR) receptor MLA1 and therefore is designated AVRA1. Here, we show that AVRA1 and the sequence-unrelated Bh effector BEC1016 (CSEP0491) suppress immunity in barley. We used yeast two-hybrid next-generation interaction screens (Y2H-NGIS), followed by binary Y2H and in planta protein-protein interactions studies, and identified a common barley target of AVRA1 and BEC1016, the endoplasmic reticulum (ER)-localized J-domain protein HvERdj3B. Silencing of this ER quality control (ERQC) protein increased Bh penetration. HvERdj3B is ER luminal, and we showed using split GFP that AVRA1 and BEC1016 translocate into the ER signal peptide-independently. Overexpression of the two effectors impeded trafficking of a vacuolar marker through the ER; silencing of HvERdj3B also exhibited this same cellular phenotype, coinciding with the effectors targeting this ERQC component. Together, these results suggest that the barley innate immunity, preventing Bh entry into epidermal cells, requires ERQC. Here, the J-domain protein HvERdj3B appears to be essential and can be regulated by AVRA1 and BEC1016. Plant disease resistance often occurs upon direct or indirect recognition of pathogen effectors by host NLR receptors. Previous work has shown that AVRA1 is directly recognized in the cytosol by the immune receptor MLA1. We speculate that the AVRA1 J-domain target being inside the ER, where it is inapproachable by NLRs, has forced the plant to evolve this challenging direct recognition.
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Affiliation(s)
- Zizhang Li
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
- Present address:
Institute for Bioscience and Biotechnology Research & Department of Plant Sciences and Landscape ArchitectureUniversity of MarylandRockvilleMarylandUSA
| | - Valeria Velásquez‐Zapata
- Program in Bioinformatics & Computational BiologyIowa State UniversityAmesIowaUSA
- Department of Plant Pathology, Entomology and MicrobiologyIowa State UniversityAmesIowaUSA
- Present address:
GreenLight Biosciences, IncResearch Triangle ParkNorth CarolinaUSA
| | - J. Mitch Elmore
- Department of Plant Pathology, Entomology and MicrobiologyIowa State UniversityAmesIowaUSA
- USDA‐Agricultural Research Service, Corn Insects and Crop Genetics Research UnitAmesIowaUSA
- Present address:
USDA‐Agricultural Research Service, Cereal Disease LaboratorySt. PaulMinnesotaUSA
| | - Xuan Li
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Wenjun Xie
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Sohini Deb
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Xiao Tian
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Sagnik Banerjee
- Program in Bioinformatics & Computational BiologyIowa State UniversityAmesIowaUSA
- Department of StatisticsIowa State UniversityAmesIowaUSA
- Present address:
Bristol Myers SquibbSan DiegoCaliforniaUSA
| | - Hans J. L. Jørgensen
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Carsten Pedersen
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Roger P. Wise
- Program in Bioinformatics & Computational BiologyIowa State UniversityAmesIowaUSA
- Department of Plant Pathology, Entomology and MicrobiologyIowa State UniversityAmesIowaUSA
- USDA‐Agricultural Research Service, Corn Insects and Crop Genetics Research UnitAmesIowaUSA
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3
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Waksman T, Astin E, Fisher SR, Hunter WN, Bos JIB. Computational Prediction of Structure, Function, and Interaction of Myzus persicae (Green Peach Aphid) Salivary Effector Proteins. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:338-346. [PMID: 38171380 DOI: 10.1094/mpmi-10-23-0154-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: 01/05/2024]
Abstract
Similar to plant pathogens, phloem-feeding insects such as aphids deliver effector proteins inside their hosts that act to promote host susceptibility and enable feeding and infestation. Despite exciting progress toward identifying and characterizing effector proteins from these insects, their functions remain largely unknown. The recent groundbreaking development in protein structure prediction algorithms, combined with the availability of proteomics and transcriptomic datasets for agriculturally important pests, provides new opportunities to explore the structural and functional diversity of effector repertoires. In this study, we sought to gain insight into the infection strategy used by the Myzus persicae (green peach aphid) by predicting and analyzing the structures of a set of 71 effector candidate proteins. We used two protein structure prediction methods, AlphaFold and OmegaFold, that produced mutually consistent results. We observed a wide continuous spectrum of structures among the effector candidates, from disordered proteins to globular enzymes. We made use of the structural information and state-of-the-art computational methods to predict M. persicae effector protein properties, including function and interaction with host plant proteins. Overall, our investigation provides novel insights into prediction of structure, function, and interaction of M. persicae effector proteins and will guide the necessary experimental characterization to address new hypotheses. [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)
- Thomas Waksman
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K
| | - Edmund Astin
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K
| | - S Ronan Fisher
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K
| | - William N Hunter
- Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K
| | - Jorunn I B Bos
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, U.K
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Yu DS, Outram MA, Smith A, McCombe CL, Khambalkar PB, Rima SA, Sun X, Ma L, Ericsson DJ, Jones DA, Williams SJ. The structural repertoire of Fusarium oxysporum f. sp. lycopersici effectors revealed by experimental and computational studies. eLife 2024; 12:RP89280. [PMID: 38411527 PMCID: PMC10942635 DOI: 10.7554/elife.89280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024] Open
Abstract
Plant pathogens secrete proteins, known as effectors, that function in the apoplast or inside plant cells to promote virulence. Effector recognition by cell-surface or cytosolic receptors results in the activation of defence pathways and plant immunity. Despite their importance, our general understanding of fungal effector function and recognition by immunity receptors remains poor. One complication often associated with effectors is their high sequence diversity and lack of identifiable sequence motifs precluding prediction of structure or function. In recent years, several studies have demonstrated that fungal effectors can be grouped into structural classes, despite significant sequence variation and existence across taxonomic groups. Using protein X-ray crystallography, we identify a new structural class of effectors hidden within the secreted in xylem (SIX) effectors from Fusarium oxysporum f. sp. lycopersici (Fol). The recognised effectors Avr1 (SIX4) and Avr3 (SIX1) represent the founding members of the Fol dual-domain (FOLD) effector class, with members containing two distinct domains. Using AlphaFold2, we predicted the full SIX effector repertoire of Fol and show that SIX6 and SIX13 are also FOLD effectors, which we validated experimentally for SIX6. Based on structural prediction and comparisons, we show that FOLD effectors are present within three divisions of fungi and are expanded in pathogens and symbionts. Further structural comparisons demonstrate that Fol secretes effectors that adopt a limited number of structural folds during infection of tomato. This analysis also revealed a structural relationship between transcriptionally co-regulated effector pairs. We make use of the Avr1 structure to understand its recognition by the I receptor, which leads to disease resistance in tomato. This study represents an important advance in our understanding of Fol-tomato, and by extension plant-fungal interactions, which will assist in the development of novel control and engineering strategies to combat plant pathogens.
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Affiliation(s)
- Daniel S Yu
- Research School of Biology, The Australian National UniversityCanberraAustralia
| | - Megan A Outram
- Research School of Biology, The Australian National UniversityCanberraAustralia
| | - Ashley Smith
- Research School of Biology, The Australian National UniversityCanberraAustralia
| | - Carl L McCombe
- Research School of Biology, The Australian National UniversityCanberraAustralia
| | - Pravin B Khambalkar
- Research School of Biology, The Australian National UniversityCanberraAustralia
| | - Sharmin A Rima
- Research School of Biology, The Australian National UniversityCanberraAustralia
| | - Xizhe Sun
- Research School of Biology, The Australian National UniversityCanberraAustralia
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, College of Life Sciences, Hebei Agriculture UniversityBaodingChina
| | - Lisong Ma
- Research School of Biology, The Australian National UniversityCanberraAustralia
- State Key Laboratory of North China Crop Improvement and Regulation, College of Horticulture, Hebei Agricultural UniversityBaodingChina
| | - Daniel J Ericsson
- Research School of Biology, The Australian National UniversityCanberraAustralia
- The Australian Nuclear Science and Technology Organisation, Australian SynchrotronClaytonAustralia
| | - David A Jones
- Research School of Biology, The Australian National UniversityCanberraAustralia
| | - Simon J Williams
- Research School of Biology, The Australian National UniversityCanberraAustralia
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Chavarro-Carrero EA, Snelders NC, Torres DE, Kraege A, López-Moral A, Petti GC, Punt W, Wieneke J, García-Velasco R, López-Herrera CJ, Seidl MF, Thomma BPHJ. The soil-borne white root rot pathogen Rosellinia necatrix expresses antimicrobial proteins during host colonization. PLoS Pathog 2024; 20:e1011866. [PMID: 38236788 PMCID: PMC10796067 DOI: 10.1371/journal.ppat.1011866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 11/27/2023] [Indexed: 01/22/2024] Open
Abstract
Rosellinia necatrix is a prevalent soil-borne plant-pathogenic fungus that is the causal agent of white root rot disease in a broad range of host plants. The limited availability of genomic resources for R. necatrix has complicated a thorough understanding of its infection biology. Here, we sequenced nine R. necatrix strains with Oxford Nanopore sequencing technology, and with DNA proximity ligation we generated a gapless assembly of one of the genomes into ten chromosomes. Whereas many filamentous pathogens display a so-called two-speed genome with more dynamic and more conserved compartments, the R. necatrix genome does not display such genome compartmentalization. It has recently been proposed that fungal plant pathogens may employ effectors with antimicrobial activity to manipulate the host microbiota to promote infection. In the predicted secretome of R. necatrix, 26 putative antimicrobial effector proteins were identified, nine of which are expressed during plant colonization. Two of the candidates were tested, both of which were found to possess selective antimicrobial activity. Intriguingly, some of the inhibited bacteria are antagonists of R. necatrix growth in vitro and can alleviate R. necatrix infection on cotton plants. Collectively, our data show that R. necatrix encodes antimicrobials that are expressed during host colonization and that may contribute to modulation of host-associated microbiota to stimulate disease development.
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Affiliation(s)
- Edgar A. Chavarro-Carrero
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Nick C. Snelders
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - David E. Torres
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Anton Kraege
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Ana López-Moral
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Gabriella C. Petti
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Wilko Punt
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Jan Wieneke
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Rómulo García-Velasco
- Laboratory of Phytopathology, Tenancingo University Center, Autonomous University of the State of Mexico, Tenancingo, State of Mexico, Mexico
| | - Carlos J. López-Herrera
- CSIC, Instituto de Agricultura Sostenible, Dept. Protección de Cultivos, C/Alameda del Obispo s/n, Córdoba, Spain
| | - Michael F. Seidl
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Bart P. H. J. Thomma
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
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6
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Qian J, Ibrahim HMM, Erz M, Kümmel F, Panstruga R, Kusch S. Long noncoding RNAs emerge from transposon-derived antisense sequences and may contribute to infection stage-specific transposon regulation in a fungal phytopathogen. Mob DNA 2023; 14:17. [PMID: 37964319 PMCID: PMC10648671 DOI: 10.1186/s13100-023-00305-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/18/2023] [Indexed: 11/16/2023] Open
Abstract
BACKGROUND The genome of the obligate biotrophic phytopathogenic barley powdery mildew fungus Blumeria hordei is inflated due to highly abundant and possibly active transposable elements (TEs). In the absence of the otherwise common repeat-induced point mutation transposon defense mechanism, noncoding RNAs could be key for regulating the activity of TEs and coding genes during the pathogenic life cycle. RESULTS We performed time-course whole-transcriptome shotgun sequencing (RNA-seq) of total RNA derived from infected barley leaf epidermis at various stages of fungal pathogenesis and observed significant transcript accumulation and time point-dependent regulation of TEs in B. hordei. Using a manually curated consensus database of 344 TEs, we discovered phased small RNAs mapping to 104 consensus transposons, suggesting that RNA interference contributes significantly to their regulation. Further, we identified 5,127 long noncoding RNAs (lncRNAs) genome-wide in B. hordei, of which 823 originated from the antisense strand of a TE. Co-expression network analysis of lncRNAs, TEs, and coding genes throughout the asexual life cycle of B. hordei points at extensive positive and negative co-regulation of lncRNAs, subsets of TEs and coding genes. CONCLUSIONS Our work suggests that similar to mammals and plants, fungal lncRNAs support the dynamic modulation of transcript levels, including TEs, during pivotal stages of host infection. The lncRNAs may support transcriptional diversity and plasticity amid loss of coding genes in powdery mildew fungi and may give rise to novel regulatory elements and virulence peptides, thus representing key drivers of rapid evolutionary adaptation to promote pathogenicity and overcome host defense.
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Affiliation(s)
- Jiangzhao Qian
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany
| | - Heba M M Ibrahim
- Department of Biosystems, Division of Plant Biotechnics, Faculty of Bioscience Engineering, Katholieke Universiteit Leuven, 3001, Leuven, Belgium
- Present address: Institute of Bio- and Geosciences IBG-2, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Myriam Erz
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany
| | - Florian Kümmel
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany
- Present address: Department of Plant-Microbe Interactions, Max Planck Institute for Plant Breeding Research, Carl-Von-Linné-Weg 10, 50829, Cologne, Germany
| | - Ralph Panstruga
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany
| | - Stefan Kusch
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany.
- Present address: Institute of Bio- and Geosciences IBG-4, Forschungszentrum Jülich, 52425, Jülich, Germany.
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7
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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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8
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Zaccaron AZ, Neill T, Corcoran J, Mahaffee WF, Stergiopoulos I. A chromosome-scale genome assembly of the grape powdery mildew pathogen Erysiphe necator reveals its genomic architecture and previously unknown features of its biology. mBio 2023; 14:e0064523. [PMID: 37341476 PMCID: PMC10470754 DOI: 10.1128/mbio.00645-23] [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: 03/16/2023] [Accepted: 04/13/2023] [Indexed: 06/22/2023] Open
Abstract
Erysiphe necator is an obligate fungal pathogen that causes grape powdery mildew, globally the most important disease on grapevines. Previous attempts to obtain a quality genome assembly for this pathogen were hindered by its high repetitive DNA content. Here, chromatin conformation capture (Hi-C) with long-read PacBio sequencing was combined to obtain a chromosome-scale assembly and a high-quality annotation for E. necator isolate EnFRAME01. The resulting 81.1 Mb genome assembly is 98% complete and consists of 34 scaffolds, 11 of which represent complete chromosomes. All chromosomes contain large centromeric-like regions and lack synteny to the 11 chromosomes of the cereal PM pathogen Blumeria graminis. Further analysis of their composition showed that repeats and transposable elements (TEs) occupy 62.7% of their content. TEs were almost evenly interspersed outside centromeric and telomeric regions and massively overlapped with regions of annotated genes, suggesting that they could have a significant functional impact. Abundant gene duplicates were observed as well, particularly in genes encoding candidate secreted effector proteins. Moreover, younger in age gene duplicates exhibited more relaxed selection pressure and were more likely to be located physically close in the genome than older duplicates. A total of 122 genes with copy number variations among six isolates of E. necator were also identified and were enriched in genes that were duplicated in EnFRAME01, indicating they may reflect an adaptive variation. Taken together, our study illuminates higher-order genomic architectural features of E. necator and provides a valuable resource for studying genomic structural variations in this pathogen. IMPORTANCE Grape powdery mildew caused by the ascomycete fungus Erysiphe necator is economically the most important and recurrent disease in vineyards across the world. The obligate biotrophic nature of E. necator hinders the use of typical genetic methods to elucidate its pathogenicity and adaptation to adverse conditions, and thus comparative genomics has been a major method to study its genome biology. However, the current reference genome of E. necator isolate C-strain is highly fragmented with many non-coding regions left unassembled. This incompleteness prohibits in-depth comparative genomic analyses and the study of genomic structural variations (SVs) that are known to affect several aspects of microbial life, including fitness, virulence, and host adaptation. By obtaining a chromosome-scale genome assembly and a high-quality gene annotation for E. necator, we reveal the organization of its chromosomal content, unearth previously unknown features of its biology, and provide a reference for studying genomic SVs in this pathogen.
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Affiliation(s)
- Alex Z. Zaccaron
- Department of Plant Pathology, University of California Davis, Davis, California, USA
| | - Tara Neill
- USDA-ARS, Horticultural Crops Disease and Pest Management Research Unit, Corvallis, Oregon, USA
| | - Jacob Corcoran
- USDA-ARS, Horticultural Crops Disease and Pest Management Research Unit, Corvallis, Oregon, USA
| | - Walter F. Mahaffee
- USDA-ARS, Horticultural Crops Disease and Pest Management Research Unit, Corvallis, Oregon, USA
| | - Ioannis Stergiopoulos
- Department of Plant Pathology, University of California Davis, Davis, California, USA
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9
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Fernandez J. The Phantom Menace: latest findings on effector biology in the rice blast fungus. ABIOTECH 2023; 4:140-154. [PMID: 37581025 PMCID: PMC10423181 DOI: 10.1007/s42994-023-00099-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 02/11/2023] [Indexed: 08/16/2023]
Abstract
Magnaporthe oryzae is a hemibiotrophic fungus responsible for the economically devastating and recalcitrant rice blast disease. However, the blast fungus is not only restricted to rice plants as it can also infect wheat, millet, and other crops. Despite previous outstanding discoveries aimed to understand and control the disease, the fungus remains one of the most important pathogens that threatens global food security. To cause disease, M. oryzae initiates morphological changes to attach, penetrate, and colonize rice cells, all while suppressing plant immune defenses that would otherwise hinder its proliferation. As such, M. oryzae actively secretes a battery of small proteins called "effectors" to manipulate host machinery. In this review, we summarize the latest findings in effector identification, expression, regulation, and functionality. We review the most studied effectors and their roles in pathogenesis. Additionally, we discern the current methodologies to structurally catalog effectors, and we highlight the importance of climate change and its impact on the future of rice blast disease.
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Affiliation(s)
- Jessie Fernandez
- Department of Microbiology and Cell Science at University of Florida-Institute of Food and Agricultural Science, Gainesville, FL 32611 USA
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10
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Kloppe T, Whetten RB, Kim SB, Powell OR, Lück S, Douchkov D, Whetten RW, Hulse-Kemp AM, Balint-Kurti P, Cowger C. Two pathogen loci determine Blumeria graminis f. sp. tritici virulence to wheat resistance gene Pm1a. THE NEW PHYTOLOGIST 2023; 238:1546-1561. [PMID: 36772855 DOI: 10.1111/nph.18809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Blumeria graminis f. sp. tritici (Bgt) is a globally important fungal pathogen of wheat that can rapidly evolve to defeat wheat powdery mildew (Pm) resistance genes. Despite periodic regional deployment of the Pm1a resistance gene in US wheat production, Bgt strains that overcome Pm1a have been notably nonpersistent in the United States, while on other continents, they are more widely established. A genome-wide association study (GWAS) was conducted to map sequence variants associated with Pm1a virulence in 216 Bgt isolates from six countries, including the United States. A virulence variant apparently unique to Bgt isolates from the United States was detected in the previously mapped gene AvrPm1a (BgtE-5612) on Bgt chromosome 6; an in vitro growth assay suggested no fitness reduction associated with this variant. A gene on Bgt chromosome 8, Bgt-51526, was shown to function as a second determinant of Pm1a virulence, and despite < 30% amino acid identity, BGT-51526 and BGTE-5612 were predicted to share > 85% of their secondary structure. A co-expression study in Nicotiana benthamiana showed that BGTE-5612 and BGT-51526 each produce a PM1A-dependent hypersensitive response. More than one member of a B. graminis effector family can be recognized by a single wheat immune receptor, and a two-gene model is necessary to explain virulence to Pm1a.
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Affiliation(s)
- Tim Kloppe
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Rebecca B Whetten
- Plant Science Research Unit, USDA Agricultural Research Service, Raleigh, NC, 27695, USA
| | - Saet-Byul Kim
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
| | | | - Stefanie Lück
- Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466, OT Gatersleben, Seeland, Germany
| | - Dimitar Douchkov
- Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466, OT Gatersleben, Seeland, Germany
| | - Ross W Whetten
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, 27695, USA
| | - Amanda M Hulse-Kemp
- Genomics and Bioinformatics Research Unit, USDA Agricultural Research Service, Raleigh, NC, 27695, USA
| | - Peter Balint-Kurti
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
- Plant Science Research Unit, USDA Agricultural Research Service, Raleigh, NC, 27695, USA
| | - Christina Cowger
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
- Plant Science Research Unit, USDA Agricultural Research Service, Raleigh, NC, 27695, USA
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11
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Seong K, Krasileva KV. Prediction of effector protein structures from fungal phytopathogens enables evolutionary analyses. Nat Microbiol 2023; 8:174-187. [PMID: 36604508 PMCID: PMC9816061 DOI: 10.1038/s41564-022-01287-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 11/11/2022] [Indexed: 01/07/2023]
Abstract
Elucidating the similarity and diversity of pathogen effectors is critical to understand their evolution across fungal phytopathogens. However, rapid divergence that diminishes sequence similarities between putatively homologous effectors has largely concealed the roots of effector evolution. Here we modelled the structures of 26,653 secreted proteins from 14 agriculturally important fungal phytopathogens, six non-pathogenic fungi and one oomycete with AlphaFold 2. With 18,000 successfully predicted folds, we performed structure-guided comparative analyses on two aspects of effector evolution: uniquely expanded sequence-unrelated structurally similar (SUSS) effector families and common folds present across the fungal species. Extreme expansion of lineage-specific SUSS effector families was found only in several obligate biotrophs, Blumeria graminis and Puccinia graminis. The highly expanded effector families were the source of conserved sequence motifs, such as the Y/F/WxC motif. We identified new classes of SUSS effector families that include known virulence factors, such as AvrSr35, AvrSr50 and Tin2. Structural comparisons revealed that the expanded structural folds further diversify through domain duplications and fusion with disordered stretches. Putatively sub- and neo-functionalized SUSS effectors could reconverge on regulation, expanding the functional pools of effectors in the pathogen infection cycle. We also found evidence that many effector families could have originated from ancestral folds conserved across fungi. Collectively, our study highlights diverse effector evolution mechanisms and supports divergent evolution as a major force in driving SUSS effector evolution from ancestral proteins.
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Affiliation(s)
- Kyungyong Seong
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Ksenia V Krasileva
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
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12
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Todd JNA, Carreón-Anguiano KG, Islas-Flores I, Canto-Canché B. Fungal Effectoromics: A World in Constant Evolution. Int J Mol Sci 2022; 23:13433. [PMID: 36362218 PMCID: PMC9656242 DOI: 10.3390/ijms232113433] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/25/2022] [Accepted: 10/31/2022] [Indexed: 10/28/2023] Open
Abstract
Effectors are small, secreted molecules that mediate the establishment of interactions in nature. While some concepts of effector biology have stood the test of time, this area of study is ever-evolving as new effectors and associated characteristics are being revealed. In the present review, the different characteristics that underly effector classifications are discussed, contrasting past and present knowledge regarding these molecules to foster a more comprehensive understanding of effectors for the reader. Research gaps in effector identification and perspectives for effector application in plant disease management are also presented, with a focus on fungal effectors in the plant-microbe interaction and interactions beyond the plant host. In summary, the review provides an amenable yet thorough introduction to fungal effector biology, presenting noteworthy examples of effectors and effector studies that have shaped our present understanding of the field.
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Affiliation(s)
- Jewel Nicole Anna Todd
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Karla Gisel Carreón-Anguiano
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Ignacio Islas-Flores
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Blondy Canto-Canché
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
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13
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Tarallo M, McDougal RL, Chen Z, Wang Y, Bradshaw RE, Mesarich CH. Characterization of two conserved cell death elicitor families from the Dothideomycete fungal pathogens Dothistroma septosporum and Fulvia fulva (syn. Cladosporium fulvum). Front Microbiol 2022; 13:964851. [PMID: 36160260 PMCID: PMC9493481 DOI: 10.3389/fmicb.2022.964851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/15/2022] [Indexed: 11/25/2022] Open
Abstract
Dothistroma septosporum (Ds) and Fulvia fulva (Ff; previously called Cladosporium fulvum) are two closely related Dothideomycete fungal species that cause Dothistroma needle blight in pine and leaf mold in tomato, respectively. During host colonization, these pathogens secrete virulence factors termed effectors to promote infection. In the presence of corresponding host immune receptors, however, these effectors activate plant defenses, including a localized cell death response that halts pathogen growth. We identified two apoplastic effector protein families, Ecp20 and Ecp32, which are conserved between the two pathogens. The Ecp20 family has four paralogues in both species, while the Ecp32 family has four paralogues in D. septosporum and five in F. fulva. Both families have members that are highly expressed during host infection. Members of the Ecp20 family have predicted structural similarity to proteins with a β-barrel fold, including the Alt a 1 allergen from Alternaria alternata, while members of the Ecp32 family have predicted structural similarity to proteins with a β-trefoil fold, such as trypsin inhibitors and lectins. Using Agrobacterium tumefaciens-mediated transient transformation assays, each family member was assessed for its ability to trigger cell death in leaves of the non-host species Nicotiana benthamiana and N. tabacum. Using this approach, FfEcp20-2, DsEcp20-3, and FfEcp20-3 from the Ecp20 family, and all members from the Ecp32 family, except for the Ds/FfEcp32-4 pair, triggered cell death in both species. This cell death was dependent on secretion of the effectors to the apoplast. In line with recognition by an extracellular immune receptor, cell death triggered by Ds/FfEcp20-3 and FfEcp32-3 was compromised in N. benthamiana silenced for BAK1 or SOBIR1, which encode extracellular co-receptors involved in transducing defense response signals following apoplastic effector recognition. We then investigated whether DsEcp20-3 and DsEcp20-4 triggered cell death in the host species Pinus radiata by directly infiltrating purified protein into pine needles. Strikingly, as in the non-host species, DsEcp20-3 triggered cell death, while DsEcp20-4 did not. Collectively, our study describes two new candidate effector families with cell death-eliciting activity from D. septosporum and F. fulva and provides evidence that members of these families are recognized by plant immune receptors.
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Affiliation(s)
- Mariana Tarallo
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | | | - Zhiyuan Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Yan Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Rosie E. Bradshaw
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Carl H. Mesarich
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
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14
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Ancient variation of the AvrPm17 gene in powdery mildew limits the effectiveness of the introgressed rye Pm17 resistance gene in wheat. Proc Natl Acad Sci U S A 2022; 119:e2108808119. [PMID: 35857869 PMCID: PMC9335242 DOI: 10.1073/pnas.2108808119] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Domesticated and wild wheat relatives provide an important source of new immune receptors for wheat resistance breeding against fungal pathogens. The durability of these resistance genes is variable and difficult to predict, yet it is crucial for effective resistance breeding. We identified a fungal effector protein recognized by an immune receptor introgressed from rye to wheat. We found that variants of the effector allowing the fungus to overcome the resistance are ancient. They were already present in the wheat powdery mildew gene pool before the introgression of the immune receptor and are therefore responsible for the rapid resistance breakdown. Our study demonstrates that the effort to identify durable resistance genes cannot be dissociated from studies of pathogen avirulence genes. Introgressions of chromosomal segments from related species into wheat are important sources of resistance against fungal diseases. The durability and effectiveness of introgressed resistance genes upon agricultural deployment is highly variable—a phenomenon that remains poorly understood, as the corresponding fungal avirulence genes are largely unknown. Until its breakdown, the Pm17 resistance gene introgressed from rye to wheat provided broad resistance against powdery mildew (Blumeria graminis). Here, we used quantitative trait locus (QTL) mapping to identify the corresponding wheat mildew avirulence effector AvrPm17. It is encoded by two paralogous genes that exhibit signatures of reoccurring gene conversion events and are members of a mildew sublineage specific effector cluster. Extensive haplovariant mining in wheat mildew and related sublineages identified several ancient virulent AvrPm17 variants that were present as standing genetic variation in wheat powdery mildew prior to the Pm17 introgression, thereby paving the way for the rapid breakdown of the Pm17 resistance. QTL mapping in mildew identified a second genetic component likely corresponding to an additional resistance gene present on the 1AL.1RS translocation carrying Pm17. This gene remained previously undetected due to suppressed recombination within the introgressed rye chromosomal segment. We conclude that the initial effectiveness of 1AL.1RS was based on simultaneous introgression of two genetically linked resistance genes. Our results demonstrate the relevance of pathogen-based genetic approaches to disentangling complex resistance loci in wheat. We propose that identification and monitoring of avirulence gene diversity in pathogen populations become an integral part of introgression breeding to ensure effective and durable resistance in wheat.
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15
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Outram MA, Figueroa M, Sperschneider J, Williams SJ, Dodds PN. Seeing is believing: Exploiting advances in structural biology to understand and engineer plant immunity. CURRENT OPINION IN PLANT BIOLOGY 2022; 67:102210. [PMID: 35461025 DOI: 10.1016/j.pbi.2022.102210] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/27/2022] [Accepted: 03/06/2022] [Indexed: 06/14/2023]
Abstract
Filamentous plant pathogens cause disease in numerous economically important crops. These pathogens secrete virulence proteins, termed effectors, that modulate host cellular processes and promote infection. Plants have evolved immunity receptors that detect effectors and activate defence pathways, resulting in resistance to the invading pathogen. This leads to an evolutionary arms race between pathogen and host that is characterised by highly diverse effector repertoires in plant pathogens. Here, we review the recent advances in understanding host-pathogen co-evolution provided by the structural determination of effectors alone, and in complex with immunity receptors. We highlight the use of recent advances in structural prediction within this field and its role for future development of designer resistance proteins.
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Affiliation(s)
- Megan A Outram
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Melania Figueroa
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT, Australia
| | - Jana Sperschneider
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT, Australia
| | - Simon J Williams
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia.
| | - Peter N Dodds
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT, Australia.
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16
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Seong K, Krasileva KV. Computational Structural Genomics Unravels Common Folds and Novel Families in the Secretome of Fungal Phytopathogen Magnaporthe oryzae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1267-1280. [PMID: 34415195 PMCID: PMC9447291 DOI: 10.1094/mpmi-03-21-0071-r] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Structural biology has the potential to illuminate the evolution of pathogen effectors and their commonalities that cannot be readily detected at the primary sequence level. Recent breakthroughs in protein structure modeling have demonstrated the feasibility to predict the protein folds without depending on homologous templates. These advances enabled a genome-wide computational structural biology approach to help understand proteins based on their predicted folds. In this study, we employed structure prediction methods on the secretome of the destructive fungal pathogen Magnaporthe oryzae. Out of 1,854 secreted proteins, we predicted the folds of 1,295 proteins (70%). We showed that template-free modeling by TrRosetta captured 514 folds missed by homology modeling, including many known effectors and virulence factors, and that TrRosetta generally produced higher quality models for secreted proteins. Along with sensitive homology search, we employed structure-based clustering, defining not only homologous groups with divergent members but also sequence-unrelated structurally analogous groups. We demonstrate that this approach can reveal new putative members of structurally similar MAX effectors and novel analogous effector families present in M. oryzae and possibly in other phytopathogens. We also investigated the evolution of expanded putative ADP-ribose transferases with predicted structures. We suggest that the loss of catalytic activities of the enzymes might have led them to new evolutionary trajectories to be specialized as protein binders. Collectively, we propose that computational structural genomics approaches can be an integral part of studying effector biology and provide valuable resources that were inaccessible before the advent of machine learning-based structure prediction.[Formula: see text] Copyright © 2021 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)
- Kyungyong Seong
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, U.S.A
| | - Ksenia V. Krasileva
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, U.S.A
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17
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An automated and combinative method for the predictive ranking of candidate effector proteins of fungal plant pathogens. Sci Rep 2021; 11:19731. [PMID: 34611252 PMCID: PMC8492765 DOI: 10.1038/s41598-021-99363-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 09/16/2021] [Indexed: 01/29/2023] Open
Abstract
Fungal plant-pathogens promote infection of their hosts through the release of 'effectors'-a broad class of cytotoxic or virulence-promoting molecules. Effectors may be recognised by resistance or sensitivity receptors in the host, which can determine disease outcomes. Accurate prediction of effectors remains a major challenge in plant pathology, but if achieved will facilitate rapid improvements to host disease resistance. This study presents a novel tool and pipeline for the ranking of predicted effector candidates-Predector-which interfaces with multiple software tools and methods, aggregates disparate features that are relevant to fungal effector proteins, and applies a pairwise learning to rank approach. Predector outperformed a typical combination of secretion and effector prediction methods in terms of ranking performance when applied to a curated set of confirmed effectors derived from multiple species. We present Predector ( https://github.com/ccdmb/predector ) as a useful tool for the ranking of predicted effector candidates, which also aggregates and reports additional supporting information relevant to effector and secretome prediction in a simple, efficient, and reproducible manner.
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18
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Yuan H, Jin C, Pei H, Zhao L, Li X, Li J, Huang W, Fan R, Liu W, Shen QH. The Powdery Mildew Effector CSEP0027 Interacts With Barley Catalase to Regulate Host Immunity. FRONTIERS IN PLANT SCIENCE 2021; 12:733237. [PMID: 34567043 PMCID: PMC8458882 DOI: 10.3389/fpls.2021.733237] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/19/2021] [Indexed: 06/01/2023]
Abstract
Powdery mildew is one of the most important fungal pathogen diseases. The genome of barley mildew fungus, Blumeria graminis f. sp. hordei (Bgh), encodes a large number of candidate secreted effector proteins (CSEPs). So far, the function and mechanism of most CSEPs remain largely unknown. Here, we identify a Bgh effector CSEP0027, a member of family 41, triggering cell death in Nicotiana benthamiana. CSEP0027 contains a functional signal peptide (SP), verified by yeast secretion assay. We show that CSEP0027 promotes Bgh virulence in barley infection using transient gene expression and host-induced gene silencing (HIGS). Barley catalase HvCAT1 is identified as a CSEP0027 interactor by yeast two-hybrid (Y2H) screening, and the interaction is verified in yeast, in vitro and in vivo. The coexpression of CSEP0027 and HvCAT1 in barley cells results in altered localization of HvCAT1 from the peroxisome to the nucleus. Barley stripe mosaic virus (BSMV)-silencing and transiently-induced gene silencing (TIGS) assays reveal that HvCAT1 is required for barley immunity against Bgh. We propose that CSEP0027 interacts with barley HvCAT1 to regulate the host immunity and likely reactive oxygen species (ROS) homeostasis to promote fungal virulence during barley infection.
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Affiliation(s)
- Hongbo Yuan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences (CAS), Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Cong Jin
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences (CAS), Beijing, China
| | - Hongcui Pei
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences (CAS), Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Lifang Zhao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences (CAS), Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Xue Li
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences (CAS), Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Jiali Li
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences (CAS), Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Wanting Huang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences (CAS), Beijing, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Renchun Fan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences (CAS), Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Wende Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences (CAS), Beijing, China
| | - Qian-Hua Shen
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences (CAS), Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
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19
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Jones DAB, Moolhuijzen PM, Hane JK. Remote homology clustering identifies lowly conserved families of effector proteins in plant-pathogenic fungi. Microb Genom 2021; 7. [PMID: 34468307 PMCID: PMC8715435 DOI: 10.1099/mgen.0.000637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Plant diseases caused by fungal pathogens are typically initiated by molecular interactions between 'effector' molecules released by a pathogen and receptor molecules on or within the plant host cell. In many cases these effector-receptor interactions directly determine host resistance or susceptibility. The search for fungal effector proteins is a developing area in fungal-plant pathology, with more than 165 distinct confirmed fungal effector proteins in the public domain. For a small number of these, novel effectors can be rapidly discovered across multiple fungal species through the identification of known effector homologues. However, many have no detectable homology by standard sequence-based search methods. This study employs a novel comparison method (RemEff) that is capable of identifying protein families with greater sensitivity than traditional homology-inference methods, leveraging a growing pool of confirmed fungal effector data to enable the prediction of novel fungal effector candidates by protein family association. Resources relating to the RemEff method and data used in this study are available from https://figshare.com/projects/Effector_protein_remote_homology/87965.
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Affiliation(s)
- Darcy A B Jones
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, Australia
| | - Paula M Moolhuijzen
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, Australia
| | - James K Hane
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, Australia.,Curtin Institute for Computation, Curtin University, Perth, Australia
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20
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Manser B, Koller T, Praz CR, Roulin AC, Zbinden H, Arora S, Steuernagel B, Wulff BBH, Keller B, Sánchez-Martín J. Identification of specificity-defining amino acids of the wheat immune receptor Pm2 and powdery mildew effector AvrPm2. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:993-1007. [PMID: 33629439 DOI: 10.1111/tpj.15214] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 05/23/2023]
Abstract
Plant nucleotide-binding leucine-rich repeat receptors (NLRs) act as intracellular sensors for pathogen-derived effector proteins and trigger an immune response, frequently resulting in the hypersensitive cell death response (HR) of the infected host cell. The wheat (Triticum aestivum) NLR Pm2 confers resistance against the fungal pathogen Blumeria graminis f. sp. tritici (Bgt) if the isolate contains the specific RNase-like effector AvrPm2. We identified and isolated seven new Pm2 alleles (Pm2e-i) in the wheat D-genome ancestor Aegilops tauschii and two new natural AvrPm2 haplotypes from Bgt. Upon transient co-expression in Nicotiana benthamiana, we observed a variant-specific HR of the Pm2 variants Pm2a and Pm2i towards AvrPm2 or its homolog from the AvrPm2 effector family, BgtE-5843, respectively. Through the introduction of naturally occurring non-synonymous single nucleotide polymorphisms and structure-guided mutations, we identified single amino acids in both the wheat NLR Pm2 and the fungal effector proteins AvrPm2 and BgtE-5843 responsible for the variant-specific HR of the Pm2 variants. Exchanging these amino acids led to a modified HR of the Pm2-AvrPm2 interaction and allowed the identification of the effector head epitope, a 20-amino-acid long unit of AvrPm2 involved in the HR. Swapping of the AvrPm2 head epitope to the non-HR-triggering AvrPm2 family member BgtE-5846 led to gain of a HR by Pm2a. Our study presents a molecular approach to identify crucial effector surface structures involved in the HR and demonstrates that natural and induced diversity in an immune receptor and its corresponding effectors can provide the basis for understanding and modifying NLR-effector specificity.
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Affiliation(s)
- Beatrice Manser
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland
| | - Teresa Koller
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland
| | - Coraline Rosalie Praz
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland
| | - Anne C Roulin
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland
| | - Helen Zbinden
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland
| | - Sanu Arora
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | | | | | - Beat Keller
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland
| | - Javier Sánchez-Martín
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland
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21
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Hewitt T, Müller MC, Molnár I, Mascher M, Holušová K, Šimková H, Kunz L, Zhang J, Li J, Bhatt D, Sharma R, Schudel S, Yu G, Steuernagel B, Periyannan S, Wulff B, Ayliffe M, McIntosh R, Keller B, Lagudah E, Zhang P. A highly differentiated region of wheat chromosome 7AL encodes a Pm1a immune receptor that recognizes its corresponding AvrPm1a effector from Blumeria graminis. THE NEW PHYTOLOGIST 2021; 229:2812-2826. [PMID: 33176001 PMCID: PMC8022591 DOI: 10.1111/nph.17075] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/01/2020] [Indexed: 05/05/2023]
Abstract
Pm1a, the first powdery mildew resistance gene described in wheat, is part of a complex resistance (R) gene cluster located in a distal region of chromosome 7AL that has suppressed genetic recombination. A nucleotide-binding, leucine-rich repeat (NLR) immune receptor gene was isolated using mutagenesis and R gene enrichment sequencing (MutRenSeq). Stable transformation confirmed Pm1a identity which induced a strong resistance phenotype in transgenic plants upon challenge with avirulent Blumeria graminis (wheat powdery mildew) pathogens. A high-density genetic map of a B. graminis family segregating for Pm1a avirulence combined with pathogen genome resequencing and RNA sequencing (RNAseq) identified AvrPm1a effector gene candidates. In planta expression identified an effector, with an N terminal Y/FxC motif, that induced a strong hypersensitive response when co-expressed with Pm1a in Nicotiana benthamiana. Single chromosome enrichment sequencing (ChromSeq) and assembly of chromosome 7A suggested that suppressed recombination around the Pm1a region was due to a rearrangement involving chromosomes 7A, 7B and 7D. The cloning of Pm1a and its identification in a highly rearranged region of chromosome 7A provides insight into the role of chromosomal rearrangements in the evolution of this complex resistance cluster.
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Affiliation(s)
- Tim Hewitt
- Agriculture & FoodCommonwealth Scientific & Industrial Research OrganizationGPO Box 1700CanberraACT2601Australia
- School of Life and Environmental SciencesPlant Breeding InstituteUniversity of Sydney107 Cobbitty RoadCobbittyNSW2570Australia
| | - Marion C. Müller
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107Zürich8008Switzerland
| | - István Molnár
- Centre of the Region Haná for Biotechnological and Agricultural ResearchInstitute of Experimental Botany of the Czech Academy of SciencesŠlechtitelů 31Olomouc779 00Czech Republic
| | - Martin Mascher
- OT GaterslebenLeibniz Institute of Plant Genetics and Crop Plant ResearchCorrensstr. 3Stadt SeelandD‐06466Germany
| | - Kateřina Holušová
- Centre of the Region Haná for Biotechnological and Agricultural ResearchInstitute of Experimental Botany of the Czech Academy of SciencesŠlechtitelů 31Olomouc779 00Czech Republic
| | - Hana Šimková
- Centre of the Region Haná for Biotechnological and Agricultural ResearchInstitute of Experimental Botany of the Czech Academy of SciencesŠlechtitelů 31Olomouc779 00Czech Republic
| | - Lukas Kunz
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107Zürich8008Switzerland
| | - Jianping Zhang
- Agriculture & FoodCommonwealth Scientific & Industrial Research OrganizationGPO Box 1700CanberraACT2601Australia
| | - Jianbo Li
- School of Life and Environmental SciencesPlant Breeding InstituteUniversity of Sydney107 Cobbitty RoadCobbittyNSW2570Australia
| | - Dhara Bhatt
- Agriculture & FoodCommonwealth Scientific & Industrial Research OrganizationGPO Box 1700CanberraACT2601Australia
| | - Raghvendra Sharma
- Agriculture & FoodCommonwealth Scientific & Industrial Research OrganizationGPO Box 1700CanberraACT2601Australia
| | - Seraina Schudel
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107Zürich8008Switzerland
| | | | | | - Sambasivam Periyannan
- Agriculture & FoodCommonwealth Scientific & Industrial Research OrganizationGPO Box 1700CanberraACT2601Australia
| | | | - Mick Ayliffe
- Agriculture & FoodCommonwealth Scientific & Industrial Research OrganizationGPO Box 1700CanberraACT2601Australia
| | - Robert McIntosh
- School of Life and Environmental SciencesPlant Breeding InstituteUniversity of Sydney107 Cobbitty RoadCobbittyNSW2570Australia
| | - Beat Keller
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107Zürich8008Switzerland
| | - Evans Lagudah
- Agriculture & FoodCommonwealth Scientific & Industrial Research OrganizationGPO Box 1700CanberraACT2601Australia
- School of Life and Environmental SciencesPlant Breeding InstituteUniversity of Sydney107 Cobbitty RoadCobbittyNSW2570Australia
| | - Peng Zhang
- School of Life and Environmental SciencesPlant Breeding InstituteUniversity of Sydney107 Cobbitty RoadCobbittyNSW2570Australia
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22
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Bauer S, Yu D, Lawson AW, Saur IML, Frantzeskakis L, Kracher B, Logemann E, Chai J, Maekawa T, Schulze-Lefert P. The leucine-rich repeats in allelic barley MLA immune receptors define specificity towards sequence-unrelated powdery mildew avirulence effectors with a predicted common RNase-like fold. PLoS Pathog 2021; 17:e1009223. [PMID: 33534797 PMCID: PMC7857584 DOI: 10.1371/journal.ppat.1009223] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 12/07/2020] [Indexed: 12/15/2022] Open
Abstract
Nucleotide-binding domain leucine-rich repeat-containing receptors (NLRs) in plants can detect avirulence (AVR) effectors of pathogenic microbes. The Mildew locus a (Mla) NLR gene has been shown to confer resistance against diverse fungal pathogens in cereal crops. In barley, Mla has undergone allelic diversification in the host population and confers isolate-specific immunity against the powdery mildew-causing fungal pathogen Blumeria graminis forma specialis hordei (Bgh). We previously isolated the Bgh effectors AVRA1, AVRA7, AVRA9, AVRA13, and allelic AVRA10/AVRA22, which are recognized by matching MLA1, MLA7, MLA9, MLA13, MLA10 and MLA22, respectively. Here, we extend our knowledge of the Bgh effector repertoire by isolating the AVRA6 effector, which belongs to the family of catalytically inactive RNase-Like Proteins expressed in Haustoria (RALPHs). Using structural prediction, we also identified RNase-like folds in AVRA1, AVRA7, AVRA10/AVRA22, and AVRA13, suggesting that allelic MLA recognition specificities could detect structurally related avirulence effectors. To better understand the mechanism underlying the recognition of effectors by MLAs, we deployed chimeric MLA1 and MLA6, as well as chimeric MLA10 and MLA22 receptors in plant co-expression assays, which showed that the recognition specificity for AVRA1 and AVRA6 as well as allelic AVRA10 and AVRA22 is largely determined by the receptors' C-terminal leucine-rich repeats (LRRs). The design of avirulence effector hybrids allowed us to identify four specific AVRA10 and five specific AVRA22 aa residues that are necessary to confer MLA10- and MLA22-specific recognition, respectively. This suggests that the MLA LRR mediates isolate-specific recognition of structurally related AVRA effectors. Thus, functional diversification of multi-allelic MLA receptors may be driven by a common structural effector scaffold, which could be facilitated by proliferation of the RALPH effector family in the pathogen genome.
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Affiliation(s)
- Saskia Bauer
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Dongli Yu
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Institute of Biochemistry, University of Cologne at Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Aaron W. Lawson
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Isabel M. L. Saur
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | | | - Barbara Kracher
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Elke Logemann
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Jijie Chai
- Institute of Biochemistry, University of Cologne at Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Cluster of Excellence on Plant Sciences, Düsseldorf, Germany
| | - Takaki Maekawa
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Paul Schulze-Lefert
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Cluster of Excellence on Plant Sciences, Düsseldorf, Germany
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23
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Mukhi N, Gorenkin D, Banfield MJ. Exploring folds, evolution and host interactions: understanding effector structure/function in disease and immunity. THE NEW PHYTOLOGIST 2020; 227:326-333. [PMID: 32239533 DOI: 10.1111/nph.16563] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/02/2020] [Indexed: 06/11/2023]
Abstract
Over the past decade, tremendous progress has been made in plant pathology, broadening our understanding of how pathogens colonize their hosts. To manipulate host cell physiology and subvert plant immune responses, pathogens secrete an array of effector proteins. A co-evolutionary arms-race drives the pathogen to constantly reinvent its effector repertoire to undermine plant immunity. In turn, hosts develop novel immune receptors to maintain effector recognition and mount defences. Understanding how effectors promote disease and how they are perceived by the plant's defence network persist as major subjects in the study of plant-pathogen interactions. Here, we focus on recent advances (over roughly the last two years) in understanding structure/function relationships in effectors from bacteria and filamentous plant pathogens. Structure/function studies of bacterial effectors frequently uncover diverse catalytic activities, while structure-informed similarity searches have enabled cataloguing of filamentous pathogen effectors. We also suggest how such advances have informed the study of plant-pathogen interactions.
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Affiliation(s)
- Nitika Mukhi
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Danylo Gorenkin
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Mark J Banfield
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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24
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Sharma G, Aminedi R, Saxena D, Gupta A, Banerjee P, Jain D, Chandran D. Effector mining from the Erysiphe pisi haustorial transcriptome identifies novel candidates involved in pea powdery mildew pathogenesis. MOLECULAR PLANT PATHOLOGY 2019; 20:1506-1522. [PMID: 31603276 PMCID: PMC6804345 DOI: 10.1111/mpp.12862] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Pea powdery mildew (PM) is an important fungal disease caused by an obligate biotroph, Erysiphe pisi (Ep), which significantly impacts pea production worldwide. The phytopathogen secretes a plethora of effectors, primarily through specialized infection structures termed haustoria, to establish a dynamic relationship with its host. To identify Ep effector candidates, a cDNA library of enriched haustoria from Ep-infected pea leaves was sequenced. The Ep transcriptome encodes 622 Ep candidate secreted proteins (CSPs), of which 167 were predicted to be candidate secreted effector proteins (CSEPs). Phylogenetic analysis indicates that Ep CSEPs are highly diverse, but, unlike cereal PM CSEPs, exhibit extensive sequence similarity with effectors from other PMs. Quantitative real-time PCR of a subset of EpCSEP/CSPs revealed that the majority are preferentially expressed in haustoria and exhibit infection stage-specific expression patterns. The functional roles of EpCSEP001, EpCSEP009 and EpCSP083 were probed by host-induced gene silencing (HIGS) via a double-stranded (ds) RNA-mediated RNAi approach. Foliar application of individual EpCSEP/CSP dsRNAs resulted in a marked reduction in PM disease symptoms. These findings were consistent with microscopic and molecular studies, suggesting that these Ep CSEP/CSPs play important roles in pea PM pathogenesis. Homology modelling revealed that EpCSEP001 and EpCSEP009 are analogous to fungal ribonucleases and belong to the RALPH family of effectors. This is the first study to identify and functionally validate candidate effectors from the agriculturally relevant pea PM, and highlights the utility of transcriptomics and HIGS to elucidate the key proteins associated with Ep pathogenesis.
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Affiliation(s)
- Gunjan Sharma
- Laboratory of Plant–Microbe InteractionsRegional Centre for BiotechnologyNCR Biotech Science ClusterFaridabadHaryanaIndia
| | - Raghavendra Aminedi
- Laboratory of Plant–Microbe InteractionsRegional Centre for BiotechnologyNCR Biotech Science ClusterFaridabadHaryanaIndia
| | - Divya Saxena
- Laboratory of Plant–Microbe InteractionsRegional Centre for BiotechnologyNCR Biotech Science ClusterFaridabadHaryanaIndia
- School of Computational and Integrative SciencesJawaharlal Nehru UniversityNew DelhiIndia
| | - Arunima Gupta
- Laboratory of Plant–Microbe InteractionsRegional Centre for BiotechnologyNCR Biotech Science ClusterFaridabadHaryanaIndia
| | - Priyajit Banerjee
- Transcription Regulation Lab, Regional Centre for BiotechnologyNCR Biotech Science ClusterFaridabadHaryanaIndia
- Kalinga Institute of Industrial TechnologyBhubaneswarOrissaIndia
| | - Deepti Jain
- Transcription Regulation Lab, Regional Centre for BiotechnologyNCR Biotech Science ClusterFaridabadHaryanaIndia
| | - Divya Chandran
- Laboratory of Plant–Microbe InteractionsRegional Centre for BiotechnologyNCR Biotech Science ClusterFaridabadHaryanaIndia
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25
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The Parauncinula polyspora Draft Genome Provides Insights into Patterns of Gene Erosion and Genome Expansion in Powdery Mildew Fungi. mBio 2019; 10:mBio.01692-19. [PMID: 31551331 PMCID: PMC6759760 DOI: 10.1128/mbio.01692-19] [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] [Indexed: 02/06/2023] Open
Abstract
Powdery mildew fungi are widespread and agronomically relevant phytopathogens causing major yield losses. Their genomes have disproportionately large numbers of mobile genetic elements, and they have experienced a significant loss of highly conserved fungal genes. In order to learn more about the evolutionary history of this fungal group, we explored the genome of an Asian oak tree pathogen, Parauncinula polyspora, a species that diverged early during evolution from the remaining powdery mildew fungi. We found that the P. polyspora draft genome is comparatively compact, has a low number of protein-coding genes, and, despite the absence of a dedicated genome defense system, lacks the massive proliferation of repetitive sequences. Based on these findings, we infer an evolutionary trajectory that shaped the genomes of powdery mildew fungi. Due to their comparatively small genome size and short generation time, fungi are exquisite model systems to study eukaryotic genome evolution. Powdery mildew fungi present an exceptional case because of their strict host dependency (termed obligate biotrophy) and the atypical size of their genomes (>100 Mb). This size expansion is largely due to the pervasiveness of transposable elements on 70% of the genome and is associated with the loss of multiple conserved ascomycete genes required for a free-living lifestyle. To date, little is known about the mechanisms that drove these changes, and information on ancestral powdery mildew genomes is lacking. We report genome analysis of the early-diverged and exclusively sexually reproducing powdery mildew fungus Parauncinula polyspora, which we performed on the basis of a natural leaf epiphytic metapopulation sample. In contrast to other sequenced species of this taxonomic group, the assembled P. polyspora draft genome is surprisingly small (<30 Mb), has a higher content of conserved ascomycete genes, and is sparsely equipped with transposons (<10%), despite the conserved absence of a common defense mechanism involved in constraining repetitive elements. We speculate that transposable element spread might have been limited by this pathogen’s unique reproduction strategy and host features and further hypothesize that the loss of conserved ascomycete genes may promote the evolutionary isolation and host niche specialization of powdery mildew fungi. Limitations associated with this evolutionary trajectory might have been in part counteracted by the evolution of plastic, transposon-rich genomes and/or the expansion of gene families encoding secreted virulence proteins.
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26
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The fungal ribonuclease-like effector protein CSEP0064/BEC1054 represses plant immunity and interferes with degradation of host ribosomal RNA. PLoS Pathog 2019; 15:e1007620. [PMID: 30856238 PMCID: PMC6464244 DOI: 10.1371/journal.ppat.1007620] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 04/15/2019] [Accepted: 02/06/2019] [Indexed: 01/08/2023] Open
Abstract
The biotrophic fungal pathogen Blumeria graminis causes the powdery mildew disease of cereals and grasses. We present the first crystal structure of a B. graminis effector of pathogenicity (CSEP0064/BEC1054), demonstrating it has a ribonuclease (RNase)-like fold. This effector is part of a group of RNase-like proteins (termed RALPHs) which comprise the largest set of secreted effector candidates within the B. graminis genomes. Their exceptional abundance suggests they play crucial functions during pathogenesis. We show that transgenic expression of RALPH CSEP0064/BEC1054 increases susceptibility to infection in both monocotyledonous and dicotyledonous plants. CSEP0064/BEC1054 interacts in planta with the pathogenesis-related protein PR10. The effector protein associates with total RNA and weakly with DNA. Methyl jasmonate (MeJA) levels modulate susceptibility to aniline-induced host RNA fragmentation. In planta expression of CSEP0064/BEC1054 reduces the formation of this RNA fragment. We propose CSEP0064/BEC1054 is a pseudoenzyme that binds to host ribosomes, thereby inhibiting the action of plant ribosome-inactivating proteins (RIPs) that would otherwise lead to host cell death, an unviable interaction and demise of the fungus. Powdery mildews are common plant diseases which affect important crop plants including cereals such as wheat and barley. The fungi that cause this disease are obligate biotrophs: they have an absolute requirement for living host cells which they penetrate with feeding structures called haustoria. These fungi must be highly effective at avoiding immune recognition which would lead to death of the host cell and the pathogen. We assume they do this by delivering effector proteins to the host. While several hundred secreted effectors have been described in cereal powdery mildews, it is unknown how they work. Here, we use X-ray crystallography and nuclear magnetic resonance (NMR) spectroscopy to determine the structure and interactions of the effector CSEP0064/BEC1054, representative of the largest class of effectors resembling fungal RNases. We find that this effector binds nucleic acids. Expression of the effector in plants increases susceptibility to infection. Moreover, transgenic CSEP0064/BEC1054 expression in wheat inhibits the degradation of host ribosomal RNA induced by ribosome-inactivating proteins (RIPs). We propose a novel mechanism of action for the RNase-like effectors in powdery mildews: they may act as pseudoenzymes to inhibit the host RIPs, known components of plant immune responses that lead to host cell death.
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27
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Müller MC, Praz CR, Sotiropoulos AG, Menardo F, Kunz L, Schudel S, Oberhänsli S, Poretti M, Wehrli A, Bourras S, Keller B, Wicker T. A chromosome-scale genome assembly reveals a highly dynamic effector repertoire of wheat powdery mildew. THE NEW PHYTOLOGIST 2019; 221:2176-2189. [PMID: 30388298 PMCID: PMC6587952 DOI: 10.1111/nph.15529] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 10/02/2018] [Indexed: 05/13/2023]
Abstract
Blumeria graminis f. sp. tritici (B.g. tritici) is the causal agent of the wheat powdery mildew disease. The highly fragmented B.g. tritici genome available so far has prevented a systematic analysis of effector genes that are known to be involved in host adaptation. To study the diversity and evolution of effector genes we produced a chromosome-scale assembly of the B.g. tritici genome. The genome assembly and annotation was achieved by combining long-read sequencing with high-density genetic mapping, bacterial artificial chromosome fingerprinting and transcriptomics. We found that the 166.6 Mb B.g. tritici genome encodes 844 candidate effector genes, over 40% more than previously reported. Candidate effector genes have characteristic local genomic organization such as gene clustering and enrichment for recombination-active regions and certain transposable element families. A large group of 412 candidate effector genes shows high plasticity in terms of copy number variation in a global set of 36 isolates and of transcription levels. Our data suggest that copy number variation and transcriptional flexibility are the main drivers for adaptation in B.g. tritici. The high repeat content may play a role in providing a genomic environment that allows rapid evolution of effector genes with selection as the driving force.
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Affiliation(s)
- Marion C. Müller
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Coraline R. Praz
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Alexandros G. Sotiropoulos
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Fabrizio Menardo
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Lukas Kunz
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Seraina Schudel
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Simone Oberhänsli
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Manuel Poretti
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Andreas Wehrli
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Salim Bourras
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Beat Keller
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
| | - Thomas Wicker
- Department of Plant and Microbial BiologyUniversity of ZurichZollikerstrasse 107ZurichCH‐8008Switzerland
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28
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Liang P, Liu S, Xu F, Jiang S, Yan J, He Q, Liu W, Lin C, Zheng F, Wang X, Miao W. Powdery Mildews Are Characterized by Contracted Carbohydrate Metabolism and Diverse Effectors to Adapt to Obligate Biotrophic Lifestyle. Front Microbiol 2018; 9:3160. [PMID: 30619222 PMCID: PMC6305591 DOI: 10.3389/fmicb.2018.03160] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 12/05/2018] [Indexed: 01/08/2023] Open
Abstract
Powdery mildew is a widespread plant disease caused by obligate biotrophic fungal pathogens involving species-specific interactions between host and parasite. To gain genomic insights into the underlying obligate biotrophic mechanisms, we analyzed 15 microbial genomes covering powdery and downy mildews and rusts. We observed a genome-wide, massive contraction of multiple gene families in powdery mildews, such as enzymes in the carbohydrate metabolism pathway, when compared with ascomycete phytopathogens, while the fatty acid metabolism pathway maintained its integrity. We also observed significant differences in candidate secreted effector protein (CSEP) families between monocot and dicot powdery mildews, perhaps due to different selection forces. While CSEPs in monocot mildews are likely subject to positive selection causing rapid expansion, CSEP families in dicot mildews are shrinking under strong purifying selection. Our results not only illustrate obligate biotrophic mechanisms of powdery mildews driven by gene family evolution in nutrient metabolism, but also demonstrate how the divergence of CSEPs between monocot and dicot lineages might contribute to species-specific adaption.
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Affiliation(s)
- Peng Liang
- College of Plant Protection, Hainan University, Haikou, China.,Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou, China.,Department of Crop Genomics and Bioinformatics, College of Agronomy and Biotechnology, National Maize Improvement Center of China, China Agricultural University, Beijing, China
| | - Songyu Liu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Feng Xu
- Department of Crop Genomics and Bioinformatics, College of Agronomy and Biotechnology, National Maize Improvement Center of China, China Agricultural University, Beijing, China
| | - Shuqin Jiang
- Department of Crop Genomics and Bioinformatics, College of Agronomy and Biotechnology, National Maize Improvement Center of China, China Agricultural University, Beijing, China
| | - Jun Yan
- Department of Crop Genomics and Bioinformatics, College of Agronomy and Biotechnology, National Maize Improvement Center of China, China Agricultural University, Beijing, China
| | - Qiguang He
- College of Plant Protection, Hainan University, Haikou, China.,Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou, China
| | - Wenbo Liu
- College of Plant Protection, Hainan University, Haikou, China.,Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou, China
| | - Chunhua Lin
- College of Plant Protection, Hainan University, Haikou, China.,Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou, China
| | - Fucong Zheng
- College of Plant Protection, Hainan University, Haikou, China.,Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou, China
| | - Xiangfeng Wang
- Department of Crop Genomics and Bioinformatics, College of Agronomy and Biotechnology, National Maize Improvement Center of China, China Agricultural University, Beijing, China
| | - Weiguo Miao
- College of Plant Protection, Hainan University, Haikou, China.,Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou, China
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29
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Bourras S, Praz CR, Spanu PD, Keller B. Cereal powdery mildew effectors: a complex toolbox for an obligate pathogen. Curr Opin Microbiol 2018; 46:26-33. [DOI: 10.1016/j.mib.2018.01.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/22/2018] [Accepted: 01/31/2018] [Indexed: 01/25/2023]
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30
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Lanfranco L, Fiorilli V, Gutjahr C. Partner communication and role of nutrients in the arbuscular mycorrhizal symbiosis. THE NEW PHYTOLOGIST 2018; 220:1031-1046. [PMID: 29806959 DOI: 10.1111/nph.15230] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/11/2018] [Indexed: 05/20/2023]
Abstract
Contents Summary 1031 I. Introduction 1031 II. Interkingdom communication enabling symbiosis 1032 III. Nutritional and regulatory roles for key metabolites in the AM symbiosis 1035 IV. The plant-fungus genotype combination determines the outcome of the symbiosis 1039 V. Perspectives 1039 Acknowledgements 1041 References 1041 SUMMARY: The evolutionary and ecological success of the arbuscular mycorrhizal (AM) symbiosis relies on an efficient and multifactorial communication system for partner recognition, and on a fine-tuned and reciprocal metabolic regulation of each symbiont to reach an optimal functional integration. Besides strigolactones, N-acetylglucosamine-derivatives released by the plant were recently suggested to trigger fungal reprogramming at the pre-contact stage. Remarkably, N-acetylglucosamine-based diffusible molecules also are symbiotic signals produced by AM fungi (AMF) and clues on the mechanisms of their perception by the plant are emerging. AMF genomes and transcriptomes contain a battery of putative effector genes that may have conserved and AMF- or host plant-specific functions. Nutrient exchange is the key feature of AM symbiosis. A mechanism of phosphate transport inside fungal hyphae has been suggested, and first insights into the regulatory mechanisms of root colonization in accordance with nutrient transfer and status were obtained. The recent discovery of the dependency of AMF on fatty acid transfer from the host has offered a convincing explanation for their obligate biotrophism. Novel studies highlighted the importance of plant and fungal genotypes for the outcome of the symbiosis. These findings open new perspectives for fundamental research and application of AMF in agriculture.
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Affiliation(s)
- Luisa Lanfranco
- Department of Life Sciences and Systems Biology, University of Torino, Viale P.A. Mattioli 25, 10125, Torino, Italy
| | - Valentina Fiorilli
- Department of Life Sciences and Systems Biology, University of Torino, Viale P.A. Mattioli 25, 10125, Torino, Italy
| | - Caroline Gutjahr
- Plant Genetics, School of Life Sciences Weihenstephan, Technical University of Munich (TUM), Emil Ramann Str. 4, D-85354, Freising, Germany
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Wu Y, Ma X, Pan Z, Kale SD, Song Y, King H, Zhang Q, Presley C, Deng X, Wei CI, Xiao S. Comparative genome analyses reveal sequence features reflecting distinct modes of host-adaptation between dicot and monocot powdery mildew. BMC Genomics 2018; 19:705. [PMID: 30253736 PMCID: PMC6156980 DOI: 10.1186/s12864-018-5069-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 09/11/2018] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Powdery mildew (PM) is one of the most important and widespread plant diseases caused by biotrophic fungi. Notably, while monocot (grass) PM fungi exhibit high-level of host-specialization, many dicot PM fungi display a broad host range. To understand such distinct modes of host-adaptation, we sequenced the genomes of four dicot PM biotypes belonging to Golovinomyces cichoracearum or Oidium neolycopersici. RESULTS We compared genomes of the four dicot PM together with those of Blumeria graminis f.sp. hordei (both DH14 and RACE1 isolates), B. graminis f.sp. tritici, and Erysiphe necator infectious on barley, wheat and grapevine, respectively. We found that despite having a similar gene number (6620-6961), the PM genomes vary from 120 to 222 Mb in size. This high-level of genome size variation is indicative of highly differential transposon activities in the PM genomes. While the total number of genes in any given PM genome is only about half of that in the genomes of closely related ascomycete fungi, most (~ 93%) of the ascomycete core genes (ACGs) can be found in the PM genomes. Yet, 186 ACGs were found absent in at least two of the eight PM genomes, of which 35 are missing in some dicot PM biotypes, but present in the three monocot PM genomes, indicating remarkable, independent and perhaps ongoing gene loss in different PM lineages. Consistent with this, we found that only 4192 (3819 singleton) genes are shared by all the eight PM genomes, the remaining genes are lineage- or biotype-specific. Strikingly, whereas the three monocot PM genomes possess up to 661 genes encoding candidate secreted effector proteins (CSEPs) with families containing up to 38 members, all the five dicot PM fungi have only 116-175 genes encoding CSEPs with limited gene amplification. CONCLUSIONS Compared to monocot (grass) PM fungi, dicot PM fungi have a much smaller effectorome. This is consistent with their contrasting modes of host-adaption: while the monocot PM fungi show a high-level of host specialization, which may reflect an advanced host-pathogen arms race, the dicot PM fungi tend to practice polyphagy, which might have lessened selective pressure for escalating an with a particular host.
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Affiliation(s)
- Ying Wu
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
| | - Xianfeng Ma
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
- Hunan Provincial Key Laboratory for Germplasm Innovation and Utilization of Crop, Hunan Agricultural University, Changsha, 410128 China
| | - Zhiyong Pan
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region, Ministry of Agriculture), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070 China
| | - Shiv D. Kale
- Biocomplexity Institute, Virginia Tech, Blacksburg, VA 24061 USA
| | - Yi Song
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083 China
| | - Harlan King
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
| | - Qiong Zhang
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
| | - Christian Presley
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
| | - Xiuxin Deng
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region, Ministry of Agriculture), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070 China
| | - Cheng-I Wei
- College of Agriculture & Natural Resources, University of Maryland, College Park, MD 20742 USA
| | - Shunyuan Xiao
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742 USA
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Sabelleck B, Panstruga R. Novel jack-in-the-box effector of the barley powdery mildew pathogen? JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3511-3514. [PMID: 29947808 PMCID: PMC6022647 DOI: 10.1093/jxb/ery192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This article comments on: Nottensteiner M, Zechmann B, McCollum C, Hückelhoven R. 2018. A barley powdery mildew fungus non-autonomous retrotransposon encodes a peptide that supports penetration success on barley. Journal of Experimental Botany 69, 3745–3758.
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Affiliation(s)
- Björn Sabelleck
- RWTH Aachen University, Institute for Biology I, Unit of Plant Molecular Cell Biology, Worringerweg, Aachen, Germany
| | - Ralph Panstruga
- RWTH Aachen University, Institute for Biology I, Unit of Plant Molecular Cell Biology, Worringerweg, Aachen, Germany
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