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Spada M, Pugliesi C, Fambrini M, Pecchia S. Challenges and Opportunities Arising from Host- Botrytis cinerea Interactions to Outline Novel and Sustainable Control Strategies: The Key Role of RNA Interference. Int J Mol Sci 2024; 25:6798. [PMID: 38928507 PMCID: PMC11203536 DOI: 10.3390/ijms25126798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/18/2024] [Accepted: 06/18/2024] [Indexed: 06/28/2024] Open
Abstract
The necrotrophic plant pathogenic fungus Botrytis cinerea (Pers., 1794), the causative agent of gray mold disease, causes significant losses in agricultural production. Control of this fungal pathogen is quite difficult due to its wide host range and environmental persistence. Currently, the management of the disease is still mainly based on chemicals, which can have harmful effects not only on the environment and on human health but also because they favor the development of strains resistant to fungicides. The flexibility and plasticity of B. cinerea in challenging plant defense mechanisms and its ability to evolve strategies to escape chemicals require the development of new control strategies for successful disease management. In this review, some aspects of the host-pathogen interactions from which novel and sustainable control strategies could be developed (e.g., signaling pathways, molecules involved in plant immune mechanisms, hormones, post-transcriptional gene silencing) were analyzed. New biotechnological tools based on the use of RNA interference (RNAi) are emerging in the crop protection scenario as versatile, sustainable, effective, and environmentally friendly alternatives to the use of chemicals. RNAi-based fungicides are expected to be approved soon, although they will face several challenges before reaching the market.
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Affiliation(s)
- Maria Spada
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Claudio Pugliesi
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Marco Fambrini
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Susanna Pecchia
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
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2
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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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Zhang H, Jiao J, Zhao T, Zhao E, Li L, Li G, Zhang B, Qin QM. GERWR: Identifying the Key Pathogenicity- Associated sRNAs of Magnaporthe Oryzae Infection in Rice Based on Graph Embedding and Random Walk With Restart. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2024; 21:227-239. [PMID: 38153818 DOI: 10.1109/tcbb.2023.3348080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2023]
Abstract
Rice blast, caused by Magnaporthe oryzae(M.oryzae), is a destructive rice disease that reduces rice yield by 10% to 30% annually. It also affects other cereal crops such as barley, wheat, rye, millet, sorghum, and maize. Small RNAs (sRNAs) play an essential regulatory role in fungus-plant interaction during the fungal invasion, but studies on pathogenic sRNAs during the fungal invasion of plants based on multi-omics data integration are rare. This paper proposes a novel approach called Graph Embedding combined with Random Walk with Restart (GERWR) to identify pathogenic sRNAs based on multi-omics data integration during M.oryzae invasion. By constructing a multi-omics network (MRMO), we identified 29 pathogenic sRNAs of rice blast fungus. Further analysis revealed that these sRNAs regulate rice genes in a many-to-many relationship, playing a significant regulatory role in the pathogenesis of rice blast disease. This paper explores the pathogenic factors of rice blast disease from the perspective of multi-omics data analysis, revealing the inherent connection between pathogenic factors of different omics. It has essential scientific significance for studying the pathogenic mechanism of rice blast fungus, the rice blast fungus-rice model system, and the pathogen-host interaction in related fields.
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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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Zhao E, Dong L, Zhao H, Zhang H, Zhang T, Yuan S, Jiao J, Chen K, Sheng J, Yang H, Wang P, Li G, Qin Q. A Relationship Prediction Method for Magnaporthe oryzae-Rice Multi-Omics Data Based on WGCNA and Graph Autoencoder. J Fungi (Basel) 2023; 9:1007. [PMID: 37888263 PMCID: PMC10607591 DOI: 10.3390/jof9101007] [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: 06/14/2023] [Revised: 10/02/2023] [Accepted: 10/07/2023] [Indexed: 10/28/2023] Open
Abstract
Magnaporthe oryzae Oryzae (MoO) pathotype is a devastating fungal pathogen of rice; however, its pathogenic mechanism remains poorly understood. The current research is primarily focused on single-omics data, which is insufficient to capture the complex cross-kingdom regulatory interactions between MoO and rice. To address this limitation, we proposed a novel method called Weighted Gene Autoencoder Multi-Omics Relationship Prediction (WGAEMRP), which combines weighted gene co-expression network analysis (WGCNA) and graph autoencoder to predict the relationship between MoO-rice multi-omics data. We applied WGAEMRP to construct a MoO-rice multi-omics heterogeneous interaction network, which identified 18 MoO small RNAs (sRNAs), 17 rice genes, 26 rice mRNAs, and 28 rice proteins among the key biomolecules. Most of the mined functional modules and enriched pathways were related to gene expression, protein composition, transportation, and metabolic processes, reflecting the infection mechanism of MoO. Compared to previous studies, WGAEMRP significantly improves the efficiency and accuracy of multi-omics data integration and analysis. This approach lays out a solid data foundation for studying the biological process of MoO infecting rice, refining the regulatory network of pathogenic markers, and providing new insights for developing disease-resistant rice varieties.
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Affiliation(s)
- Enshuang Zhao
- College of Computer Science and Technology, Jilin University, Changchun 130012, China; (E.Z.); (L.D.); (H.Z.); (T.Z.); (J.J.); (K.C.); (J.S.)
| | - Liyan Dong
- College of Computer Science and Technology, Jilin University, Changchun 130012, China; (E.Z.); (L.D.); (H.Z.); (T.Z.); (J.J.); (K.C.); (J.S.)
- Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, Jilin University, Changchun 130012, China
| | - Hengyi Zhao
- College of Computer Science and Technology, Jilin University, Changchun 130012, China; (E.Z.); (L.D.); (H.Z.); (T.Z.); (J.J.); (K.C.); (J.S.)
| | - Hao Zhang
- College of Computer Science and Technology, Jilin University, Changchun 130012, China; (E.Z.); (L.D.); (H.Z.); (T.Z.); (J.J.); (K.C.); (J.S.)
- College of Software, Jilin University, Changchun 130012, China; (S.Y.); (H.Y.); (P.W.)
| | - Tianyue Zhang
- College of Computer Science and Technology, Jilin University, Changchun 130012, China; (E.Z.); (L.D.); (H.Z.); (T.Z.); (J.J.); (K.C.); (J.S.)
| | - Shuai Yuan
- College of Software, Jilin University, Changchun 130012, China; (S.Y.); (H.Y.); (P.W.)
| | - Jiao Jiao
- College of Computer Science and Technology, Jilin University, Changchun 130012, China; (E.Z.); (L.D.); (H.Z.); (T.Z.); (J.J.); (K.C.); (J.S.)
| | - Kang Chen
- College of Computer Science and Technology, Jilin University, Changchun 130012, China; (E.Z.); (L.D.); (H.Z.); (T.Z.); (J.J.); (K.C.); (J.S.)
| | - Jianhua Sheng
- College of Computer Science and Technology, Jilin University, Changchun 130012, China; (E.Z.); (L.D.); (H.Z.); (T.Z.); (J.J.); (K.C.); (J.S.)
| | - Hongbo Yang
- College of Software, Jilin University, Changchun 130012, China; (S.Y.); (H.Y.); (P.W.)
| | - Pengyu Wang
- College of Software, Jilin University, Changchun 130012, China; (S.Y.); (H.Y.); (P.W.)
| | - Guihua Li
- College of Plant Science, Key Laboratory of Zoonosis Research, Ministry of Education, Jilin University, Changchun 130012, China;
| | - Qingming Qin
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MI 65211-7310, USA;
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Regmi R, Newman TE, Khentry Y, Kamphuis LG, Derbyshire MC. Genome-wide identification of Sclerotinia sclerotiorum small RNAs and their endogenous targets. BMC Genomics 2023; 24:582. [PMID: 37784009 PMCID: PMC10544508 DOI: 10.1186/s12864-023-09686-7] [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] [Received: 06/23/2023] [Accepted: 09/19/2023] [Indexed: 10/04/2023] Open
Abstract
BACKGROUND Several phytopathogens produce small non-coding RNAs of approximately 18-30 nucleotides (nt) which post-transcriptionally regulate gene expression. Commonly called small RNAs (sRNAs), these small molecules were also reported to be present in the necrotrophic pathogen Sclerotinia sclerotiorum. S. sclerotiorum causes diseases in more than 400 plant species, including the important oilseed crop Brassica napus. sRNAs can further be classified as microRNAs (miRNAs) and short interfering RNAs (siRNAs). Certain miRNAs can activate loci that produce further sRNAs; these secondary sRNA-producing loci are called 'phased siRNA' (PHAS) loci and have only been described in plants. To date, very few studies have characterized sRNAs and their endogenous targets in S. sclerotiorum. RESULTS We used Illumina sequencing to characterize sRNAs from fungal mycelial mats of S. sclerotiorum spread over B. napus leaves. In total, eight sRNA libraries were prepared from in vitro, 12 h post-inoculation (HPI), and 24 HPI mycelial mat samples. Cluster analysis identified 354 abundant sRNA clusters with reads of more than 100 Reads Per Million (RPM). Differential expression analysis revealed upregulation of 34 and 57 loci at 12 and 24 HPI, respectively, in comparison to in vitro samples. Among these, 25 loci were commonly upregulated. Altogether, 343 endogenous targets were identified from the major RNAs of 25 loci. Almost 88% of these targets were annotated as repeat element genes, while the remaining targets were non-repeat element genes. Fungal degradome reads confirmed cleavage of two transposable elements by one upregulated sRNA. Altogether, 24 milRNA loci were predicted with both mature and milRNA* (star) sequences; these are both criteria associated previously with experimentally verified miRNAs. Degradome sequencing data confirmed the cleavage of 14 targets. These targets were related to repeat element genes, phosphate acetyltransferases, RNA-binding factor, and exchange factor. A PHAS gene prediction tool identified 26 possible phased interfering loci with 147 phasiRNAs from the S. sclerotiorum genome, suggesting this pathogen might produce sRNAs that function similarly to miRNAs in higher eukaryotes. CONCLUSIONS Our results provide new insights into sRNA populations and add a new resource for the study of sRNAs in S. sclerotiorum.
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Affiliation(s)
- Roshan Regmi
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA, 6102, Australia
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Floreat, WA, 6014, Australia
- Present address: Microbiome for One Systems Health, CSIRO, Urrbrae, South Australia, Australia
| | - Toby E Newman
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA, 6102, Australia
| | - Yuphin Khentry
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA, 6102, Australia
| | - Lars G Kamphuis
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA, 6102, Australia
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Floreat, WA, 6014, Australia
| | - Mark C Derbyshire
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA, 6102, Australia.
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Qiao SA, Gao Z, Roth R. A perspective on cross-kingdom RNA interference in mutualistic symbioses. THE NEW PHYTOLOGIST 2023; 240:68-79. [PMID: 37452489 PMCID: PMC10952549 DOI: 10.1111/nph.19122] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 05/24/2023] [Indexed: 07/18/2023]
Abstract
RNA interference (RNAi) is arguably one of the more versatile mechanisms in cell biology, facilitating the fine regulation of gene expression and protection against mobile genomic elements, whilst also constituting a key aspect of induced plant immunity. More recently, the use of this mechanism to regulate gene expression in heterospecific partners - cross-kingdom RNAi (ckRNAi) - has been shown to form a critical part of bidirectional interactions between hosts and endosymbionts, regulating the interplay between microbial infection mechanisms and host immunity. Here, we review the current understanding of ckRNAi as it relates to interactions between plants and their pathogenic and mutualistic endosymbionts, with particular emphasis on evidence in support of ckRNAi in the arbuscular mycorrhizal symbiosis.
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Affiliation(s)
- Serena A Qiao
- Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Zongyu Gao
- Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Ronelle Roth
- Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
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8
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Kusch S, Singh M, Thieron H, Spanu PD, Panstruga R. Site-specific analysis reveals candidate cross-kingdom small RNAs, tRNA and rRNA fragments, and signs of fungal RNA phasing in the barley-powdery mildew interaction. MOLECULAR PLANT PATHOLOGY 2023; 24:570-587. [PMID: 36917011 DOI: 10.1111/mpp.13324] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/17/2023] [Accepted: 02/20/2023] [Indexed: 05/18/2023]
Abstract
The establishment of host-microbe interactions requires molecular communication between both partners, which may involve the mutual transfer of noncoding small RNAs. Previous evidence suggests that this is also true for powdery mildew disease in barley, which is caused by the fungal pathogen Blumeria hordei. However, previous studies lacked spatial resolution regarding the accumulation of small RNAs upon host infection by B. hordei. Here, we analysed site-specific small RNA repertoires in the context of the barley-B. hordei interaction. To this end, we dissected infected leaves into separate fractions representing different sites that are key to the pathogenic process: epiphytic fungal mycelium, infected plant epidermis, isolated haustoria, a vesicle-enriched fraction from infected epidermis, and extracellular vesicles. Unexpectedly, we discovered enrichment of specific 31-33-base 5'-terminal fragments of barley 5.8S ribosomal RNA in extracellular vesicles and infected epidermis, as well as particular B. hordei transfer RNA fragments in haustoria. We describe canonical small RNAs from both the plant host and the fungal pathogen that may confer cross-kingdom RNA interference activity. Interestingly, we found first evidence of phased small interfering RNAs in B. hordei, a feature usually attributed to plants, which may be associated with the posttranscriptional control of fungal coding genes, pseudogenes, and transposable elements. Our data suggest a key and possibly site-specific role for cross-kingdom RNA interference and noncoding RNA fragments in the host-pathogen communication between B. hordei and its host barley.
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Affiliation(s)
- Stefan Kusch
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Aachen, Germany
| | - Mansi Singh
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Aachen, Germany
| | - Hannah Thieron
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Aachen, Germany
| | - Pietro D Spanu
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Aachen, Germany
| | - Ralph Panstruga
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Aachen, Germany
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9
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Mapuranga J, Chang J, Zhang L, Zhang N, Yang W. Fungal Secondary Metabolites and Small RNAs Enhance Pathogenicity during Plant-Fungal Pathogen Interactions. J Fungi (Basel) 2022; 9:jof9010004. [PMID: 36675825 PMCID: PMC9862911 DOI: 10.3390/jof9010004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/16/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Fungal plant pathogens use proteinaceous effectors as well as newly identified secondary metabolites (SMs) and small non-coding RNA (sRNA) effectors to manipulate the host plant's defense system via diverse plant cell compartments, distinct organelles, and many host genes. However, most molecular studies of plant-fungal interactions have focused on secreted effector proteins without exploring the possibly equivalent functions performed by fungal (SMs) and sRNAs, which are collectively known as "non-proteinaceous effectors". Fungal SMs have been shown to be generated throughout the plant colonization process, particularly in the early biotrophic stages of infection. The fungal repertoire of non-proteinaceous effectors has been broadened by the discovery of fungal sRNAs that specifically target plant genes involved in resistance and defense responses. Many RNAs, particularly sRNAs involved in gene silencing, have been shown to transmit bidirectionally between fungal pathogens and their hosts. However, there are no clear functional approaches to study the role of these SM and sRNA effectors. Undoubtedly, fungal SM and sRNA effectors are now a treasured land to seek. Therefore, understanding the role of fungal SM and sRNA effectors may provide insights into the infection process and identification of the interacting host genes that are targeted by these effectors. This review discusses the role of fungal SMs and sRNAs during plant-fungal interactions. It will also focus on the translocation of sRNA effectors across kingdoms, the application of cross-kingdom RNA interference in managing plant diseases and the tools that can be used to predict and study these non-proteinaceous effectors.
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10
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RoyChowdhury M, Sternhagen J, Xin Y, Lou B, Li X, Li C. Evolution of pathogenicity in obligate fungal pathogens and allied genera. PeerJ 2022; 10:e13794. [PMID: 36042858 PMCID: PMC9420410 DOI: 10.7717/peerj.13794] [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: 08/06/2021] [Accepted: 07/06/2022] [Indexed: 01/17/2023] Open
Abstract
Obligate fungal pathogens (ascomycetes and basidiomycetes) and oomycetes are known to cause diseases in cereal crop plants. They feed on living cells and most of them have learned to bypass the host immune machinery. This paper discusses some of the factors that are associated with pathogenicity drawing examples from ascomycetes, basidiomycetes and oomycetes, with respect to their manifestation in crop plants. The comparisons have revealed a striking similarity in the three groups suggesting convergent pathways that have arisen from three lineages independently leading to an obligate lifestyle. This review has been written with the intent, that new information on adaptation strategies of biotrophs, modifications in pathogenicity strategies and population dynamics will improve current strategies for breeding with stable resistance.
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Affiliation(s)
- Moytri RoyChowdhury
- Infectious Diseases Program, California Department of Public Health, Richmond, California, United States of America
| | - Jake Sternhagen
- Riverside School of Medicine, University of California, Riverside, Riverside, CA, United States of America
| | - Ya Xin
- Hangzhou Academy of Agricultural Sciences, Hangzhou, P.R. China
| | - Binghai Lou
- Guangxi Academy of Specialty Crops, Guilin, Guangxi, P.R. China
| | - Xiaobai Li
- Zhejiang Academy of Agricultural Sciences, Hangzhou, P.R. China
| | - Chunnan Li
- Hangzhou Academy of Agricultural Sciences, Hangzhou, P.R. China
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11
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Schlemmer T, Lischka R, Wegner L, Ehlers K, Biedenkopf D, Koch A. Extracellular vesicles isolated from dsRNA-sprayed barley plants exhibit no growth inhibition or gene silencing in Fusarium graminearum. Fungal Biol Biotechnol 2022; 9:14. [PMID: 35836276 PMCID: PMC9284790 DOI: 10.1186/s40694-022-00143-w] [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: 09/28/2021] [Accepted: 06/14/2022] [Indexed: 11/11/2022] Open
Abstract
Numerous reports have shown that incorporating a double-stranded RNA (dsRNA)-expressing transgene into plants or applying dsRNA by spraying it onto their leaves successfully protects them against invading pathogens exploiting the mechanism of RNA interference (RNAi). How dsRNAs or siRNAs are transferred between donor host cells and recipient fungal cells is largely unknown. It is speculated that plant extracellular vesicles (EVs) function as RNA shuttles between plants and their pathogens. Recently, we found that EVs isolated from host-induced gene silencing (HIGS) or spray-induced gene silencing (SIGS) plants contained dsRNA-derived siRNAs. In this study, we evaluated whether isolated EVs from dsRNA-sprayed barley (Hordeum vulgare) plants affected the growth of the phytopathogenic ascomycete Fusarium graminearum. Encouraged by our previous finding that dropping barley-derived EVs on F. graminearum cultures caused fungal stress phenotypes, we conducted an in vitro growth experiment in microtiter plates where we co-cultivated F. graminearum with plant EVs isolated from dsRNA-sprayed barley leaves. We observed that co-cultivation of F. graminearum macroconidia with barley EVs did not affect fungal growth. Furthermore, plant EVs containing SIGS-derived siRNA appeared not to affect F. graminearum growth and showed no gene silencing activity on F. graminearum CYP51 genes. Based on our findings, we concluded that either the amount of SIGS-derived siRNA was insufficient to induce target gene silencing in F. graminearum, indicating that the role of EVs in SIGS is minor, or that F. graminearum uptake of plant EVs from liquid cultures was inefficient or impossible.
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Affiliation(s)
- Timo Schlemmer
- Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology, Justus Liebig University, Heinrich-Buff-Ring 26, 35392, Giessen, Germany.,Institute of Phytomedicine, University of Hohenheim, Otto-Sander-Strasse 5, 70599, Stuttgart, Germany
| | - Richard Lischka
- Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology, Justus Liebig University, Heinrich-Buff-Ring 26, 35392, Giessen, Germany
| | - Linus Wegner
- Intitute of Botany, Justus Liebig University, Heinrich-Buff-Ring 38, 35292, Giessen, Germany
| | - Katrin Ehlers
- Intitute of Botany, Justus Liebig University, Heinrich-Buff-Ring 38, 35292, Giessen, Germany
| | - Dagmar Biedenkopf
- Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology, Justus Liebig University, Heinrich-Buff-Ring 26, 35392, Giessen, Germany
| | - Aline Koch
- Institute of Phytomedicine, University of Hohenheim, Otto-Sander-Strasse 5, 70599, Stuttgart, Germany.
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12
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The ectomycorrhizal fungus Pisolithus microcarpus encodes a microRNA involved in cross-kingdom gene silencing during symbiosis. Proc Natl Acad Sci U S A 2022; 119:2103527119. [PMID: 35012977 PMCID: PMC8784151 DOI: 10.1073/pnas.2103527119] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2021] [Indexed: 11/23/2022] Open
Abstract
Plant genomes encode hundreds of genes controlling the detection, signaling pathways, and immune responses necessary to defend against pathogens. Pathogens, in turn, continually evolve to evade these defenses. Small RNAs, such as microRNAs (miRNAs), are one mechanism used by pathogens to overcome plant defenses and facilitate plant colonization. Mounting evidence would suggest that beneficial microbes, likewise, use miRNAs to facilitate symbiosis. Here, we demonstrate that the beneficial fungus Pisolithus microcarpus encodes a miRNA that enters plant cells and stabilizes the symbiotic interaction. These results demonstrate that beneficial fungi may regulate host gene expression through the use of miRNAs and sheds light on how beneficial microbes have evolved mechanisms to colonize plant tissues. Small RNAs (sRNAs) are known to regulate pathogenic plant–microbe interactions. Emerging evidence from the study of these model systems suggests that microRNAs (miRNAs) can be translocated between microbes and plants to facilitate symbiosis. The roles of sRNAs in mutualistic mycorrhizal fungal interactions, however, are largely unknown. In this study, we characterized miRNAs encoded by the ectomycorrhizal fungus Pisolithus microcarpus and investigated their expression during mutualistic interaction with Eucalyptus grandis. Using sRNA sequencing data and in situ miRNA detection, a novel fungal miRNA, Pmic_miR-8, was found to be transported into E. grandis roots after interaction with P. microcarpus. Further characterization experiments demonstrate that inhibition of Pmic_miR-8 negatively impacts the maintenance of mycorrhizal roots in E. grandis, while supplementation of Pmic_miR-8 led to deeper integration of the fungus into plant tissues. Target prediction and experimental testing suggest that Pmic_miR-8 may target the host NB-ARC domain containing transcripts, suggesting a potential role for this miRNA in subverting host signaling to stabilize the symbiotic interaction. Altogether, we provide evidence of previously undescribed cross-kingdom sRNA transfer from ectomycorrhizal fungi to plant roots, shedding light onto the involvement of miRNAs during the developmental process of mutualistic symbioses.
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13
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Saur IML, Hückelhoven R. Recognition and defence of plant-infecting fungal pathogens. JOURNAL OF PLANT PHYSIOLOGY 2021; 256:153324. [PMID: 33249386 DOI: 10.1016/j.jplph.2020.153324] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 11/04/2020] [Accepted: 11/04/2020] [Indexed: 06/12/2023]
Abstract
Attempted infections of plants with fungi result in diverse outcomes ranging from symptom-less resistance to severe disease and even death of infected plants. The deleterious effect on crop yield have led to intense focus on the cellular and molecular mechanisms that explain the difference between resistance and susceptibility. This research has uncovered plant resistance or susceptibility genes that explain either dominant or recessive inheritance of plant resistance with many of them coding for receptors that recognize pathogen invasion. Approaches based on cell biology and phytochemistry have contributed to identifying factors that halt an invading fungal pathogen from further invasion into or between plant cells. Plant chemical defence compounds, antifungal proteins and structural reinforcement of cell walls appear to slow down fungal growth or even prevent fungal penetration in resistant plants. Additionally, the hypersensitive response, in which a few cells undergo a strong local immune reaction, including programmed cell death at the site of infection, stops in particular biotrophic fungi from spreading into surrounding tissue. In this review, we give a general overview of plant recognition and defence of fungal parasites tracing back to the early 20th century with a special focus on Triticeae and on the progress that was made in the last 30 years.
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Affiliation(s)
- Isabel M L Saur
- Max Planck Institute for Plant Breeding Research, Department of Plant-Microbe Interactions, Carl-von-Linné-Weg 10, 50829 Cologne, Germany.
| | - Ralph Hückelhoven
- Phytopathology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Ramann-Straße 2, 85354 Freising, Germany.
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14
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Lax C, Tahiri G, Patiño-Medina JA, Cánovas-Márquez JT, Pérez-Ruiz JA, Osorio-Concepción M, Navarro E, Calo S. The Evolutionary Significance of RNAi in the Fungal Kingdom. Int J Mol Sci 2020; 21:E9348. [PMID: 33302447 PMCID: PMC7763443 DOI: 10.3390/ijms21249348] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/18/2022] Open
Abstract
RNA interference (RNAi) was discovered at the end of last millennium, changing the way scientists understood regulation of gene expression. Within the following two decades, a variety of different RNAi mechanisms were found in eukaryotes, reflecting the evolutive diversity that RNAi entails. The essential silencing mechanism consists of an RNase III enzyme called Dicer that cleaves double-stranded RNA (dsRNA) generating small interfering RNAs (siRNAs), a hallmark of RNAi. These siRNAs are loaded into the RNA-induced silencing complex (RISC) triggering the cleavage of complementary messenger RNAs by the Argonaute protein, the main component of the complex. Consequently, the expression of target genes is silenced. This mechanism has been thoroughly studied in fungi due to their proximity to the animal phylum and the conservation of the RNAi mechanism from lower to higher eukaryotes. However, the role and even the presence of RNAi differ across the fungal kingdom, as it has evolved adapting to the particularities and needs of each species. Fungi have exploited RNAi to regulate a variety of cell activities as different as defense against exogenous and potentially harmful DNA, genome integrity, development, drug tolerance, or virulence. This pathway has offered versatility to fungi through evolution, favoring the enormous diversity this kingdom comprises.
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Affiliation(s)
- Carlos Lax
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - Ghizlane Tahiri
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - José Alberto Patiño-Medina
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia, Michoacán CP 58030, Mexico;
| | - José T. Cánovas-Márquez
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - José A. Pérez-Ruiz
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - Macario Osorio-Concepción
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - Eusebio Navarro
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - Silvia Calo
- School of Natural and Exact Sciences, Pontificia Universidad Católica Madre y Maestra, 51033 Santiago de los Caballeros, Dominican Republic
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15
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Zhang T, Chang H, Zhang B, Liu S, Zhao T, Zhao E, Zhao H, Zhang H. Transboundary Pathogenic microRNA Analysis Framework for Crop Fungi Driven by Biological Big Data and Artificial Intelligence Model. Comput Biol Chem 2020; 89:107401. [PMID: 33068919 DOI: 10.1016/j.compbiolchem.2020.107401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/19/2020] [Accepted: 10/05/2020] [Indexed: 12/13/2022]
Abstract
Plant fungal diseases have been affecting the world's agricultural production and economic levels for a long time, such as rice blast, gray tomato mold, potato late blight etc. Recent studies have shown that fungal pathogens transmit microRNA as an effector to host plants for infection. However, bioassay-based verification analysis is time-consuming and challenging, and it is difficult to analyze from a global perspective. With the accumulation of fungal and plant-related data, data analysis methods can be used to analyze pathogenic fungal microRNA further. Based on the microRNA expression data of fungal pathogens infecting plants before and after, this paper discusses the selection strategy of sample data, the extraction strategy of pathogenic fungal microRNA, the prediction strategy of a fungal pathogenic microRNA target gene, the bicluster-based fungal pathogenic microRNA functional analysis strategy and experimental verification methods. A general analysis pipeline based on machine learning and bicluster-based function module was proposed for plant-fungal pathogenic microRNA.The pipeline proposed in this paper is applied to the infection process of Magnaporthe oryzae and the infection process of potato late blight. It has been verified to prove the feasibility of the pipeline. It can be extended to other relevant crop pathogen research, providing a new idea for fungal research on plant diseases. It can be used as a reference for understanding the interaction between fungi and plants.
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Affiliation(s)
- Tianyue Zhang
- College of Computer Science and Technology, Jilin University, China
| | - Haowu Chang
- College of Computer Science and Technology, Jilin University, China
| | - Borui Zhang
- Columbia Independent School, Columbia, MO, USA
| | - Sifei Liu
- College of Computer Science and Technology, Jilin University, China
| | - Tianheng Zhao
- College of Computer Science and Technology, Jilin University, China
| | - Enshuang Zhao
- College of Computer Science and Technology, Jilin University, China
| | - Hengyi Zhao
- College of Computer Science and Technology, Jilin University, China
| | - Hao Zhang
- College of Computer Science and Technology, Jilin University, China.
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16
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Jaswal R, Kiran K, Rajarammohan S, Dubey H, Singh PK, Sharma Y, Deshmukh R, Sonah H, Gupta N, Sharma TR. Effector Biology of Biotrophic Plant Fungal Pathogens: Current Advances and Future Prospects. Microbiol Res 2020; 241:126567. [PMID: 33080488 DOI: 10.1016/j.micres.2020.126567] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 07/21/2020] [Accepted: 07/25/2020] [Indexed: 12/13/2022]
Abstract
The interaction of fungal pathogens with their host requires a novel invading mechanism and the presence of various virulence-associated components responsible for promoting the infection. The small secretory proteins, explicitly known as effector proteins, are one of the prime mechanisms of host manipulation utilized by the pathogen to disarm the host. Several effector proteins are known to translocate from fungus to the plant cell for host manipulation. Many fungal effectors have been identified using genomic, transcriptomic, and bioinformatics approaches. Most of the effector proteins are devoid of any conserved signatures, and their prediction based on sequence homology is very challenging, therefore by combining the sequence consensus based upon machine learning features, multiple tools have also been developed for predicting apoplastic and cytoplasmic effectors. Various post-genomics approaches like transcriptomics of virulent isolates have also been utilized for identifying active consortia of effectors. Significant progress has been made in understanding biotrophic effectors; however, most of it is underway due to their complex interaction with host and complicated recognition and signaling networks. This review discusses advances, and challenges in effector identification and highlighted various features of the potential effector proteins and approaches for understanding their genetics and strategies for regulation.
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Affiliation(s)
- Rajdeep Jaswal
- National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, 140306, India; Department of Microbiology, Panjab University, Chandigarh, Punjab, 160014, India
| | - Kanti Kiran
- ICAR-National Institute for Plant Biotechnology, Pusa Campus New Delhi, 110012, India
| | | | - Himanshu Dubey
- ICAR-National Institute for Plant Biotechnology, Pusa Campus New Delhi, 110012, India
| | - Pankaj Kumar Singh
- National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, 140306, India
| | - Yogesh Sharma
- National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, 140306, India
| | - Rupesh Deshmukh
- National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, 140306, India
| | - Humira Sonah
- National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, 140306, India
| | - Naveen Gupta
- Department of Microbiology, Panjab University, Chandigarh, Punjab, 160014, India.
| | - T R Sharma
- National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, 140306, India.
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17
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Dunker F, Trutzenberg A, Rothenpieler JS, Kuhn S, Pröls R, Schreiber T, Tissier A, Kemen A, Kemen E, Hückelhoven R, Weiberg A. Oomycete small RNAs bind to the plant RNA-induced silencing complex for virulence. eLife 2020; 9:56096. [PMID: 32441255 PMCID: PMC7297541 DOI: 10.7554/elife.56096] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 05/21/2020] [Indexed: 12/21/2022] Open
Abstract
The exchange of small RNAs (sRNAs) between hosts and pathogens can lead to gene silencing in the recipient organism, a mechanism termed cross-kingdom RNAi (ck-RNAi). While fungal sRNAs promoting virulence are established, the significance of ck-RNAi in distinct plant pathogens is not clear. Here, we describe that sRNAs of the pathogen Hyaloperonospora arabidopsidis, which represents the kingdom of oomycetes and is phylogenetically distant from fungi, employ the host plant’s Argonaute (AGO)/RNA-induced silencing complex for virulence. To demonstrate H. arabidopsidis sRNA (HpasRNA) functionality in ck-RNAi, we designed a novel CRISPR endoribonuclease Csy4/GUS reporter that enabled in situ visualization of HpasRNA-induced target suppression in Arabidopsis. The significant role of HpasRNAs together with AtAGO1 in virulence was revealed in plant atago1 mutants and by transgenic Arabidopsis expressing a short-tandem-target-mimic to block HpasRNAs, that both exhibited enhanced resistance. HpasRNA-targeted plant genes contributed to host immunity, as Arabidopsis gene knockout mutants displayed quantitatively enhanced susceptibility.
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Affiliation(s)
- Florian Dunker
- Faculty of Biology, Genetics, Biocenter Martinsried, LMU Munich, Martinsried, Germany
| | - Adriana Trutzenberg
- Faculty of Biology, Genetics, Biocenter Martinsried, LMU Munich, Martinsried, Germany
| | - Jan S Rothenpieler
- Faculty of Biology, Genetics, Biocenter Martinsried, LMU Munich, Martinsried, Germany
| | - Sarah Kuhn
- Faculty of Biology, Genetics, Biocenter Martinsried, LMU Munich, Martinsried, Germany
| | - Reinhard Pröls
- Phytopathology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Tom Schreiber
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Halle, Germany
| | - Alain Tissier
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Halle, Germany
| | - Ariane Kemen
- Center for Plant Molecular Biology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Eric Kemen
- Center for Plant Molecular Biology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Ralph Hückelhoven
- Phytopathology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Arne Weiberg
- Faculty of Biology, Genetics, Biocenter Martinsried, LMU Munich, Martinsried, Germany
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18
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Schaefer LK, Parlange F, Buchmann G, Jung E, Wehrli A, Herren G, Müller MC, Stehlin J, Schmid R, Wicker T, Keller B, Bourras S. Cross-Kingdom RNAi of Pathogen Effectors Leads to Quantitative Adult Plant Resistance in Wheat. FRONTIERS IN PLANT SCIENCE 2020; 11:253. [PMID: 32211008 PMCID: PMC7076181 DOI: 10.3389/fpls.2020.00253] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/18/2020] [Indexed: 05/30/2023]
Abstract
Cross-kingdom RNA interference (RNAi) is a biological process allowing plants to transfer small regulatory RNAs to invading pathogens to trigger the silencing of target virulence genes. Transient assays in cereal powdery mildews suggest that silencing of one or two effectors could lead to near loss of virulence, but evidence from stable RNAi lines is lacking. We established transient host-induced gene silencing (HIGS) in wheat, and demonstrate that targeting an essential housekeeping gene in the wheat powdery mildew pathogen (Blumeria graminis f. sp. tritici) results in significant reduction of virulence at an early stage of infection. We generated stable transgenic RNAi wheat lines encoding a HIGS construct simultaneously silencing three B.g. tritici effectors including SvrPm3 a1/f1 , a virulence factor involved in the suppression of the Pm3 powdery mildew resistance gene. We show that all targeted effectors are effectively downregulated by HIGS, resulting in reduced fungal virulence on adult wheat plants. Our findings demonstrate that stable HIGS of effector genes can lead to quantitative gain of resistance without major pleiotropic effects in wheat.
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Affiliation(s)
| | - Francis Parlange
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Gabriele Buchmann
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Esther Jung
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Andreas Wehrli
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Gerhard Herren
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Marion Claudia Müller
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Jonas Stehlin
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Roman Schmid
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Thomas Wicker
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Beat Keller
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Salim Bourras
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
- Department of Forest Mycology and Plant Pathology, Division of Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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19
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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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20
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Gaffar FY, Imani J, Karlovsky P, Koch A, Kogel KH. Different Components of the RNA Interference Machinery Are Required for Conidiation, Ascosporogenesis, Virulence, Deoxynivalenol Production, and Fungal Inhibition by Exogenous Double-Stranded RNA in the Head Blight Pathogen Fusarium graminearum. Front Microbiol 2019; 10:1662. [PMID: 31616385 PMCID: PMC6764512 DOI: 10.3389/fmicb.2019.01662] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 07/04/2019] [Indexed: 12/21/2022] Open
Abstract
In filamentous fungi, gene silencing through RNA interference (RNAi) shapes many biological processes, including pathogenicity. We explored the requirement of key components of fungal RNAi machineries, including DICER-like 1 and 2 (FgDCL1, FgDCL2), ARGONAUTE 1 and 2 (FgAGO1, FgAGO2), AGO-interacting protein FgQIP (QDE2-interacting protein), RecQ helicase (FgQDE3), and four RNA-dependent RNA polymerases (FgRdRP1, FgRdRP2, FgRdRP3, FgRdRP4), in the ascomycete mycotoxin-producing fungal pathogen Fusarium graminearum (Fg) for sexual and asexual multiplication, pathogenicity, and its sensitivity to double-stranded (ds)RNA. We corroborate and extend earlier findings that conidiation, ascosporogenesis, and Fusarium head blight (FHB) symptom development require an operable RNAi machinery. The involvement of RNAi in conidiation is dependent on environmental conditions as it is detectable only under low light (<2 μmol m−2 s−1). Although both DCLs and AGOs partially share their functions, the sexual ascosporogenesis is mediated primarily by FgDCL1 and FgAGO2, while FgDCL2 and FgAGO1 contribute to asexual conidia formation and germination. FgDCL1 and FgAGO2 also account for pathogenesis as their knockout (KO) results in reduced FHB development. Apart from KO mutants Δdcl2 and Δago1, mutants Δrdrp2, Δrdrp3, Δrdrp4, Δqde3, and Δqip are strongly compromised for conidiation, while KO mutations in all RdPRs, QDE3, and QIP strongly affect ascosporogenesis. Analysis of trichothecenes mycotoxins in wheat kernels showed that the relative amount of deoxynivalenol (DON), calculated as [DON] per amount of fungal genomic DNA was reduced in all spikes infected with RNAi mutants, suggesting the possibility that the fungal RNAi pathways affect Fg’s DON production. Moreover, silencing of fungal genes by exogenous target gene-specific double-stranded RNA (dsRNA) (spray-induced gene silencing, SIGS) is dependent on DCLs, AGOs, and QIP, but not on QDE3. Together these data show that in F. graminearum, different key components of the RNAi machinery are crucial in different steps of fungal development and pathogenicity.
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Affiliation(s)
- Fatima Yousif Gaffar
- Department of Phytopathology, Centre for BioSystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany
| | - Jafargholi Imani
- Department of Phytopathology, Centre for BioSystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany
| | - Petr Karlovsky
- Department of Crop Sciences, Molecular Phytopathology and Mycotoxin Research, University of Göttingen, Göttingen, Germany
| | - Aline Koch
- Department of Phytopathology, Centre for BioSystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany
| | - Karl-Heinz Kogel
- Department of Phytopathology, Centre for BioSystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany
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21
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Hunt M, Banerjee S, Surana P, Liu M, Fuerst G, Mathioni S, Meyers BC, Nettleton D, Wise RP. Small RNA discovery in the interaction between barley and the powdery mildew pathogen. BMC Genomics 2019; 20:610. [PMID: 31345162 PMCID: PMC6657096 DOI: 10.1186/s12864-019-5947-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 06/30/2019] [Indexed: 01/04/2023] Open
Abstract
Background Plants encounter pathogenic and non-pathogenic microorganisms on a nearly constant basis. Small RNAs such as siRNAs and miRNAs/milRNAs influence pathogen virulence and host defense responses. We exploited the biotrophic interaction between the powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh), and its diploid host plant, barley (Hordeum vulgare) to explore fungal and plant sRNAs expressed during Bgh infection of barley leaf epidermal cells. Results RNA was isolated from four fast-neutron immune-signaling mutants and their progenitor over a time course representing key stages of Bgh infection, including appressorium formation, penetration of epidermal cells, and development of haustorial feeding structures. The Cereal Introduction (CI) 16151 progenitor carries the resistance allele Mla6, while Bgh isolate 5874 harbors the AVRa6 avirulence effector, resulting in an incompatible interaction. Parallel Analysis of RNA Ends (PARE) was used to verify sRNAs with likely transcript targets in both barley and Bgh. Bgh sRNAs are predicted to regulate effectors, metabolic genes, and translation-related genes. Barley sRNAs are predicted to influence the accumulation of transcripts that encode auxin response factors, NAC transcription factors, homeodomain transcription factors, and several splicing factors. We also identified phasing small interfering RNAs (phasiRNAs) in barley that overlap transcripts that encode receptor-like kinases (RLKs) and nucleotide-binding, leucine-rich domain proteins (NLRs). Conclusions These data suggest that Bgh sRNAs regulate gene expression in metabolism, translation-related, and pathogen effectors. PARE-validated targets of predicted Bgh milRNAs include both EKA (effectors homologous to AVRk1 and AVRa10) and CSEP (candidate secreted effector protein) families. We also identified barley phasiRNAs and miRNAs in response to Bgh infection. These include phasiRNA loci that overlap with a significant proportion of receptor-like kinases, suggesting an additional sRNA control mechanism may be active in barley leaves as opposed to predominant R-gene phasiRNA overlap in many eudicots. In addition, we identified conserved miRNAs, novel miRNA candidates, and barley genome mapped sRNAs that have PARE validated transcript targets in barley. The miRNA target transcripts are enriched in transcription factors, signaling-related proteins, and photosynthesis-related proteins. Together these results suggest both barley and Bgh control metabolism and infection-related responses via the specific accumulation and targeting of genes via sRNAs. Electronic supplementary material The online version of this article (10.1186/s12864-019-5947-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matt Hunt
- Interdepartmental Genetics & Genomics, Iowa State University, Ames, Iowa, 50011, USA.,Department of Plant Pathology & Microbiology, Iowa State University, Ames, Iowa, 50011, USA
| | - Sagnik Banerjee
- Department of Plant Pathology & Microbiology, Iowa State University, Ames, Iowa, 50011, USA.,Interdepartmental Bioinformatics & Computational Biology, Iowa State University, Ames, Iowa, 50011, USA
| | - Priyanka Surana
- Department of Plant Pathology & Microbiology, Iowa State University, Ames, Iowa, 50011, USA.,Interdepartmental Bioinformatics & Computational Biology, Iowa State University, Ames, Iowa, 50011, USA
| | - Meiling Liu
- Interdepartmental Bioinformatics & Computational Biology, Iowa State University, Ames, Iowa, 50011, USA.,Department of Statistics, Iowa State University, Ames, Iowa, 50011, USA
| | - Greg Fuerst
- Corn Insects and Crop Genetics Research, USDA-Agricultural Research Service, Iowa State University, Ames, Iowa, 50011, USA
| | - Sandra Mathioni
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA.,Division of Plant Sciences, University of Missouri - Columbia, 52 Agriculture Lab, Columbia, MO, 65211, USA
| | - Dan Nettleton
- Interdepartmental Bioinformatics & Computational Biology, Iowa State University, Ames, Iowa, 50011, USA.,Department of Statistics, Iowa State University, Ames, Iowa, 50011, USA
| | - Roger P Wise
- Interdepartmental Genetics & Genomics, Iowa State University, Ames, Iowa, 50011, USA. .,Department of Plant Pathology & Microbiology, Iowa State University, Ames, Iowa, 50011, USA. .,Interdepartmental Bioinformatics & Computational Biology, Iowa State University, Ames, Iowa, 50011, USA. .,Corn Insects and Crop Genetics Research, USDA-Agricultural Research Service, Iowa State University, Ames, Iowa, 50011, USA.
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22
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Polonio Á, Seoane P, Claros MG, Pérez-García A. The haustorial transcriptome of the cucurbit pathogen Podosphaera xanthii reveals new insights into the biotrophy and pathogenesis of powdery mildew fungi. BMC Genomics 2019; 20:543. [PMID: 31272366 PMCID: PMC6611051 DOI: 10.1186/s12864-019-5938-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 06/26/2019] [Indexed: 12/11/2022] Open
Abstract
Background Podosphaera xanthii is the main causal agent of powdery mildew disease in cucurbits and is responsible for important yield losses in these crops worldwide. Powdery mildew fungi are obligate biotrophs. In these parasites, biotrophy is determined by the presence of haustoria, which are specialized structures of parasitism developed by these fungi for the acquisition of nutrients and the delivery of effectors. Detailed molecular studies of powdery mildew haustoria are scarce due mainly to difficulties in their isolation. Therefore, their analysis is considered an important challenge for powdery mildew research. The aim of this work was to gain insights into powdery mildew biology by analysing the haustorial transcriptome of P. xanthii. Results Prior to RNA isolation and massive-scale mRNA sequencing, a flow cytometric approach was developed to isolate P. xanthii haustoria free of visible contaminants. Next, several commercial kits were used to isolate total RNA and to construct the cDNA and Illumina libraries that were finally sequenced by the Illumina NextSeq system. Using this approach, the maximum amount of information from low-quality RNA that could be obtained was used to accomplish the de novo assembly of the P. xanthii haustorial transcriptome. The subsequent analysis of this transcriptome and comparison with the epiphytic transcriptome allowed us to identify the importance of several biological processes for haustorial cells such as protection against reactive oxygen species, the acquisition of different nutrients and genetic regulation mediated by non-coding RNAs. In addition, we could also identify several secreted proteins expressed exclusively in haustoria such as cell adhesion proteins that have not been related to powdery mildew biology to date. Conclusions This work provides a novel approach to study the molecular aspects of powdery mildew haustoria. In addition, the results of this study have also allowed us to identify certain previously unknown processes and proteins involved in the biology of powdery mildews that could be essential for their biotrophy and pathogenesis. Electronic supplementary material The online version of this article (10.1186/s12864-019-5938-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Álvaro Polonio
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Bulevar Louis Pasteur 31, 29071, Málaga, Spain.,Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Bulevar Louis Pasteur 31, 29071, Málaga, Spain
| | - Pedro Seoane
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Bulevar Louis Pasteur 31, 29071, Málaga, Spain
| | - M Gonzalo Claros
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Bulevar Louis Pasteur 31, 29071, Málaga, Spain
| | - Alejandro Pérez-García
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Bulevar Louis Pasteur 31, 29071, Málaga, Spain. .,Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Bulevar Louis Pasteur 31, 29071, Málaga, Spain.
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23
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Collemare J, O'Connell R, Lebrun MH. Nonproteinaceous effectors: the terra incognita of plant-fungal interactions. THE NEW PHYTOLOGIST 2019; 223:590-596. [PMID: 30851201 DOI: 10.1111/nph.15785] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 02/22/2019] [Indexed: 05/27/2023]
Abstract
Molecular plant-fungal interaction studies have mainly focused on small secreted protein effectors. However, accumulating evidence shows that numerous fungal secondary metabolites are produced at all stages of plant colonization, especially during early asymptomatic/biotrophic phases. The discovery of fungal small RNAs targeting plant transcripts has expanded the fungal repertoire of nonproteinaceous effectors even further. The challenge now is to develop specific functional methods to fully understand the biological roles of these effectors. Studies on fungal extracellular vesicles are also needed because they could be the universal carriers of all kinds of fungal effectors. With this review, we aim to stimulate the nonproteinaceous effector research field to move from descriptive to functional studies, which should bring a paradigm shift in plant-fungal interactions.
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Affiliation(s)
- Jérôme Collemare
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
| | - Richard O'Connell
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, F78850, Thiverval-Grignon, France
| | - Marc-Henri Lebrun
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, F78850, Thiverval-Grignon, France
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24
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Post-Translational Modifications of Proteins Have Versatile Roles in Regulating Plant Immune Responses. Int J Mol Sci 2019; 20:ijms20112807. [PMID: 31181758 PMCID: PMC6600372 DOI: 10.3390/ijms20112807] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/01/2019] [Accepted: 06/06/2019] [Indexed: 12/14/2022] Open
Abstract
To protect themselves from pathogens, plants have developed an effective innate immune system. Plants recognize pathogens and then rapidly alter signaling pathways within individual cells in order to achieve an appropriate immune response, including the generation of reactive oxygen species, callose deposition, and transcriptional reprogramming. Post-translational modifications (PTMs) are versatile regulatory changes critical for plant immune response processes. Significantly, PTMs are involved in the crosstalk that serves as a fine-tuning mechanism to adjust cellular responses to pathogen infection. Here, we provide an overview of PTMs that mediate defense signaling perception, signal transduction in host cells, and downstream signal activation.
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