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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: 0] [Impact Index Per Article: 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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2
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Cheng AP, Kwon S, Adeshara T, Göhre V, Feldbrügge M, Weiberg A. Extracellular RNAs released by plant-associated fungi: from fundamental mechanisms to biotechnological applications. Appl Microbiol Biotechnol 2023; 107:5935-5945. [PMID: 37572124 PMCID: PMC10485130 DOI: 10.1007/s00253-023-12718-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/15/2023] [Accepted: 07/19/2023] [Indexed: 08/14/2023]
Abstract
Extracellular RNAs are an emerging research topic in fungal-plant interactions. Fungal plant pathogens and symbionts release small RNAs that enter host cells to manipulate plant physiology and immunity. This communication via extracellular RNAs between fungi and plants is bidirectional. On the one hand, plants release RNAs encapsulated inside extracellular vesicles as a defense response as well as for intercellular and inter-organismal communication. On the other hand, recent reports suggest that also full-length mRNAs are transported within fungal EVs into plants, and these fungal mRNAs might get translated inside host cells. In this review article, we summarize the current views and fundamental concepts of extracellular RNAs released by plant-associated fungi, and we discuss new strategies to apply extracellular RNAs in crop protection against fungal pathogens. KEY POINTS: • Extracellular RNAs are an emerging topic in plant-fungal communication. • Fungi utilize RNAs to manipulate host plants for colonization. • Extracellular RNAs can be engineered to protect plants against fungal pathogens.
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Affiliation(s)
- An-Po Cheng
- Faculty of Biology, Ludwig-Maximilians Universität München (LMU), 82152, Martinsried, Germany
| | - Seomun Kwon
- Institute for Microbiology, Heinrich Heine Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Trusha Adeshara
- Institute for Microbiology, Heinrich Heine Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Vera Göhre
- Institute for Microbiology, Heinrich Heine Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Michael Feldbrügge
- Institute for Microbiology, Heinrich Heine Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Arne Weiberg
- Faculty of Biology, Ludwig-Maximilians Universität München (LMU), 82152, Martinsried, Germany.
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3
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Mann CWG, Sawyer A, Gardiner DM, Mitter N, Carroll BJ, Eamens AL. RNA-Based Control of Fungal Pathogens in Plants. Int J Mol Sci 2023; 24:12391. [PMID: 37569766 PMCID: PMC10418863 DOI: 10.3390/ijms241512391] [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: 06/28/2023] [Revised: 08/01/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
Our duty to conserve global natural ecosystems is increasingly in conflict with our need to feed an expanding population. The use of conventional pesticides not only damages the environment and vulnerable biodiversity but can also still fail to prevent crop losses of 20-40% due to pests and pathogens. There is a growing call for more ecologically sustainable pathogen control measures. RNA-based biopesticides offer an eco-friendly alternative to the use of conventional fungicides for crop protection. The genetic modification (GM) of crops remains controversial in many countries, though expression of transgenes inducing pathogen-specific RNA interference (RNAi) has been proven effective against many agronomically important fungal pathogens. The topical application of pathogen-specific RNAi-inducing sprays is a more responsive, GM-free approach to conventional RNAi transgene-based crop protection. The specific targeting of essential pathogen genes, the development of RNAi-nanoparticle carrier spray formulations, and the possible structural modifications to the RNA molecules themselves are crucial to the success of this novel technology. Here, we outline the current understanding of gene silencing pathways in plants and fungi and summarize the pioneering and recent work exploring RNA-based biopesticides for crop protection against fungal pathogens, with a focus on spray-induced gene silencing (SIGS). Further, we discuss factors that could affect the success of RNA-based control strategies, including RNA uptake, stability, amplification, and movement within and between the plant host and pathogen, as well as the cost and design of RNA pesticides.
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Affiliation(s)
- Christopher W. G. Mann
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (C.W.G.M.); (A.S.); (B.J.C.)
| | - Anne Sawyer
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (C.W.G.M.); (A.S.); (B.J.C.)
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.M.G.); (N.M.)
| | - Donald M. Gardiner
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.M.G.); (N.M.)
| | - Neena Mitter
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.M.G.); (N.M.)
| | - Bernard J. Carroll
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (C.W.G.M.); (A.S.); (B.J.C.)
| | - Andrew L. Eamens
- School of Health, University of the Sunshine Coast, Maroochydore, QLD 4558, Australia
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4
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Singewar K, Fladung M. Double-stranded RNA (dsRNA) technology to control forest insect pests and fungal pathogens: challenges and opportunities. Funct Integr Genomics 2023; 23:185. [PMID: 37243792 DOI: 10.1007/s10142-023-01107-y] [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: 07/04/2022] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 05/29/2023]
Abstract
Climate change alters the seasonal synchronization between plants and respective pests plus pathogens. The geographical infiltration helps to shift their hosts, resulting in novel outbreaks that damage forests and ecology. Traditional management schemes are unable to control such outbreaks, therefore unconventional and competitive governance is needed to manage forest pests and pathogens. RNA interference (RNAi) mediated double-stranded RNA (dsRNA) treatment method can be implemented to protect forest trees. Exogenous dsRNA triggers the RNAi-mediated gene silencing of a vital gene, and suspends protein production, resulting in the death of targeted pathogens and pests. The dsRNA treatment method is successful for many crop insects and fungi, however, studies of dsRNA against forest pests and pathogens are depleting. Pesticides and fungicides based on dsRNA could be used to combat pathogens that caused outbreaks in different parts of the world. Although the dsRNA has proved its potential, the crucial dilemma and risks including species-specific gene selection, and dsRNA delivery methods cannot be overlooked. Here, we summarized the major fungi pathogens and insect pests that have caused outbreaks, their genomic information, and studies on dsRNA fungi-and pesticides. Current challenges and opportunities in dsRNA target decision, delivery using nanoparticles, direct applications, and a new method using mycorrhiza for forest tree protection are discussed. The importance of affordable next-generation sequencing to minimize the impact on non-target species is discussed. We suggest that collaborative research among forest genomics and pathology institutes could develop necessary dsRNA strategies to protect forest tree species.
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Affiliation(s)
- Kiran Singewar
- Thünen Institute of Forest Genetics, 22927, Großhansdorf, Germany.
| | - Matthias Fladung
- Thünen Institute of Forest Genetics, 22927, Großhansdorf, Germany.
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Walker PL, Ziegler DJ, Giesbrecht S, McLoughlin A, Wan J, Khan D, Hoi V, Whyard S, Belmonte MF. Control of white mold (Sclerotinia sclerotiorum) through plant-mediated RNA interference. Sci Rep 2023; 13:6477. [PMID: 37081036 PMCID: PMC10119085 DOI: 10.1038/s41598-023-33335-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 04/11/2023] [Indexed: 04/22/2023] Open
Abstract
The causative agent of white mold, Sclerotinia sclerotiorum, is capable of infecting over 600 plant species and is responsible for significant crop losses across the globe. Control is currently dependent on broad-spectrum chemical agents that can negatively impact the agroecological environment, presenting a need to develop alternative control measures. In this study, we developed transgenic Arabidopsis thaliana (AT1703) expressing hairpin (hp)RNA to silence S. sclerotiorum ABHYDROLASE-3 and slow infection through host induced gene silencing (HIGS). Leaf infection assays show reduced S. sclerotiorum lesion size, fungal load, and ABHYDROLASE-3 transcript abundance in AT1703 compared to wild-type Col-0. To better understand how HIGS influences host-pathogen interactions, we performed global RNA sequencing on AT1703 and wild-type Col-0 directly at the site of S. sclerotiorum infection. RNA sequencing data reveals enrichment of the salicylic acid (SA)-mediated systemic acquired resistance (SAR) pathway, as well as transcription factors predicted to regulate plant immunity. Using RT-qPCR, we identified predicted interacting partners of ABHYDROLASE-3 in the polyamine synthesis pathway of S. sclerotiorum that demonstrate co-reduction with ABHYDROLASE-3 transcript levels during infection. Together, these results demonstrate the utility of HIGS technology in slowing S. sclerotiorum infection and provide insight into the role of ABHYDROLASE-3 in the A. thaliana-S. sclerotiorum pathosystem.
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Affiliation(s)
- Philip L Walker
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Dylan J Ziegler
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Shayna Giesbrecht
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Austein McLoughlin
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Joey Wan
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Deirdre Khan
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Vanessa Hoi
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Steve Whyard
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Mark F Belmonte
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
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Dalakouras A, Katsaouni A, Avramidou M, Dadami E, Tsiouri O, Vasileiadis S, Makris A, Georgopoulou ME, Papadopoulou KK. A beneficial fungal root endophyte triggers systemic RNA silencing and DNA methylation of a host reporter gene. RNA Biol 2023; 20:20-30. [PMID: 36573793 PMCID: PMC9809956 DOI: 10.1080/15476286.2022.2159158] [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] [Indexed: 12/28/2022] Open
Abstract
A growing body of evidence suggests that RNA interference (RNAi) plays a pivotal role in the communication between plants and pathogenic fungi, where a bi-directional trans-kingdom RNAi is established to the advantage of either the host or the pathogen. Similar mechanisms acting during plant association with non-pathogenic symbiotic microorganisms have been elusive to this date. To determine whether root endophytes can induce systemic RNAi responses to their host plants, we designed an experimental reporter-based system consisting of the root-restricted, beneficial fungal endophyte, Fusarium solani strain K (FsK) and its host Nicotiana benthamiana. Since not all fungi encode the RNAi machinery, we first needed to validate that FsK does so, by identifying its core RNAi enzymes (2 Dicer-like genes, 2 Argonautes and 4 RNA-dependent RNA polymerases) and by showing its susceptibility to in vitro RNAi upon exogenous application of double stranded RNAs (dsRNAs). Upon establishing this, we transformed FsK with a hairpin RNA (hpRNA) construct designed to target a reporter gene in its host N. benthamiana. The hpRNA was processed by FsK RNAi machinery predominantly into 21-24-nt small RNAs that triggered RNA silencing but not DNA methylation in the fungal hyphae. Importantly, when the hpRNA-expressing FsK was used to inoculate N. benthamiana, systemic RNA silencing and DNA methylation of the host reporter gene was recorded. Our data suggest that RNAi signals can be translocated by root endophytes to their hosts and can modulate gene expression during mutualism, which may be translated to beneficial phenotypes.
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Affiliation(s)
- Athanasios Dalakouras
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece,Hellenic Agricultural Organization Demeter, Institute of Industrial and Forage Crops, Larissa, Greece,CONTACT Athanasios Dalakouras University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece; Hellenic Agricultural Organization Demeter, Institute of Industrial and Forage Crops, Larissa, Greece
| | - Afrodite Katsaouni
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
| | - Marianna Avramidou
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
| | - Elena Dadami
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
| | - Olga Tsiouri
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
| | - Sotirios Vasileiadis
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
| | - Athanasios Makris
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
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7
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Ray P, Sahu D, Aminedi R, Chandran D. Concepts and considerations for enhancing RNAi efficiency in phytopathogenic fungi for RNAi-based crop protection using nanocarrier-mediated dsRNA delivery systems. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:977502. [PMID: 37746174 PMCID: PMC10512274 DOI: 10.3389/ffunb.2022.977502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/19/2022] [Indexed: 09/26/2023]
Abstract
Existing, emerging, and reemerging strains of phytopathogenic fungi pose a significant threat to agricultural productivity globally. This risk is further exacerbated by the lack of resistance source(s) in plants or a breakdown of resistance by pathogens through co-evolution. In recent years, attenuation of essential pathogen gene(s) via double-stranded (ds) RNA-mediated RNA interference (RNAi) in host plants, a phenomenon known as host-induced gene silencing, has gained significant attention as a way to combat pathogen attack. Yet, due to biosafety concerns regarding transgenics, country-specific GMO legislation has limited the practical application of desirable attributes in plants. The topical application of dsRNA/siRNA targeting essential fungal gene(s) through spray-induced gene silencing (SIGS) on host plants has opened up a transgene-free avenue for crop protection. However, several factors influence the outcome of RNAi, including but not limited to RNAi mechanism in plant/fungi, dsRNA/siRNA uptake efficiency, dsRNA/siRNA design parameters, dsRNA stability and delivery strategy, off-target effects, etc. This review emphasizes the significance of these factors and suggests appropriate measures to consider while designing in silico and in vitro experiments for successful RNAi in open-field conditions. We also highlight prospective nanoparticles as smart delivery vehicles for deploying RNAi molecules in plant systems for long-term crop protection and ecosystem compatibility. Lastly, we provide specific directions for future investigations that focus on blending nanotechnology and RNAi-based fungal control for practical applications.
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Affiliation(s)
- Poonam Ray
- Laboratory of Plant-Microbe Interactions, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Debashish Sahu
- Laboratory of Plant-Microbe Interactions, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Raghavendra Aminedi
- Division of Genomic Resources, ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
| | - Divya Chandran
- Laboratory of Plant-Microbe Interactions, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
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8
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Yoshimoto R, Ishida F, Yamaguchi M, Tanaka S. The production and secretion of tRNA-derived RNA fragments in the corn smut fungus Ustilago maydis. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:958798. [PMID: 37746175 PMCID: PMC10512261 DOI: 10.3389/ffunb.2022.958798] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/18/2022] [Indexed: 09/26/2023]
Abstract
The biogenesis of small non-coding RNAs is a molecular event that contributes to cellular functions. The basidiomycete fungus Ustilago maydis is a biotrophic pathogen parasitizing maize. A hallmark of its genome structure is an absence of RNAi machinery including Dicer and Argonaute proteins, which are responsible for the production of small RNAs in other organisms. However, it remains unclear whether U. maydis produces small RNAs during fungal growth. Here we found that U. maydis cells accumulate approximately 20-30 nucleotides of small RNA fragments during growth in the axenic culture condition. The RNA-seq analysis of these fragments identified that these small RNAs are originated from tRNAs and 5.8S ribosomal RNA. Interestingly, majority of their sequences are generated from tRNAs responsible for asparagine, glutamine and glycine, suggesting a bias of origin. The cleavage of tRNAs mainly occurs at the position near anticodon-stem-loop. We generated the deletion mutants of two genes nuc1 and nuc2 encoding RNase T2, which is a candidate enzyme that cleaves tRNAs. The deletion mutants of two genes largely fail to accumulate tRNA-derived RNA fragments. Nuc1 and tRNA are co-localized at the tip of budding cells and tRNA fragment could be detected in culture supernatant. Our results suggest that specific tRNAs would be cleaved during secretory processes and tRNA fragments might have extracellular functions.
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Affiliation(s)
- Rei Yoshimoto
- Faculty of Agriculture, Setsunan University, Osaka, Japan
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9
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Ciofini A, Negrini F, Baroncelli R, Baraldi E. Management of Post-Harvest Anthracnose: Current Approaches and Future Perspectives. PLANTS 2022; 11:plants11141856. [PMID: 35890490 PMCID: PMC9319655 DOI: 10.3390/plants11141856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 11/16/2022]
Abstract
Anthracnose is a severe disease caused by Colletotrichum spp. on several crop species. Fungal infections can occur both in the field and at the post-harvest stage causing severe lesions on fruits and economic losses. Physical treatments and synthetic fungicides have traditionally been the preferred means to control anthracnose adverse effects; however, the urgent need to decrease the use of toxic chemicals led to the investigation of innovative and sustainable protection techniques. Evidence for the efficacy of biological agents and vegetal derivates has been reported; however, their introduction into actual crop protection strategies requires the solutions of several critical issues. Biotechnology-based approaches have also been explored, revealing the opportunity to develop innovative and safe methods for anthracnose management through genome editing and RNA interference technologies. Nevertheless, besides the number of advantages related to their use, e.g., the putative absence of adverse effects due to their high specificity, a number of aspects remain to be clarified to enable their introduction into Integrated Pest Management (IPM) protocols against Colletotrichum spp. disease.
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Roles of RNA silencing in viral and non-viral plant immunity and in the crosstalk between disease resistance systems. Nat Rev Mol Cell Biol 2022; 23:645-662. [PMID: 35710830 DOI: 10.1038/s41580-022-00496-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2022] [Indexed: 11/08/2022]
Abstract
RNA silencing is a well-established antiviral immunity system in plants, in which small RNAs guide Argonaute proteins to targets in viral RNA or DNA, resulting in virus repression. Virus-encoded suppressors of silencing counteract this defence system. In this Review, we discuss recent findings about antiviral RNA silencing, including the movement of RNA through plasmodesmata and the differentiation between plant self and viral RNAs. We also discuss the emerging role of RNA silencing in plant immunity against non-viral pathogens. This immunity is mediated by transkingdom movement of RNA into and out of the infected plant cells in vesicles or as extracellular nucleoproteins and, like antiviral immunity, is influenced by the silencing suppressors encoded in the pathogens' genomes. Another effect of RNA silencing on general immunity involves host-encoded small RNAs, including microRNAs, that regulate NOD-like receptors and defence signalling pathways in the innate immunity system of plants. These RNA silencing pathways form a network of processes with both positive and negative effects on the immune systems of plants.
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11
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RNAi as a Foliar Spray: Efficiency and Challenges to Field Applications. Int J Mol Sci 2022; 23:ijms23126639. [PMID: 35743077 PMCID: PMC9224206 DOI: 10.3390/ijms23126639] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/10/2022] [Accepted: 06/13/2022] [Indexed: 02/04/2023] Open
Abstract
RNA interference (RNAi) is a powerful tool that is being increasingly utilized for crop protection against viruses, fungal pathogens, and insect pests. The non-transgenic approach of spray-induced gene silencing (SIGS), which relies on spray application of double-stranded RNA (dsRNA) to induce RNAi, has come to prominence due to its safety and environmental benefits in addition to its wide host range and high target specificity. However, along with promising results in recent studies, several factors limiting SIGS RNAi efficiency have been recognized in insects and plants. While sprayed dsRNA on the plant surface can produce a robust RNAi response in some chewing insects, plant uptake and systemic movement of dsRNA is required for delivery to many other target organisms. For example, pests such as sucking insects require the presence of dsRNA in vascular tissues, while many fungal pathogens are predominately located in internal plant tissues. Investigating the mechanisms by which sprayed dsRNA enters and moves through plant tissues and understanding the barriers that may hinder this process are essential for developing efficient ways to deliver dsRNA into plant systems. In this review, we assess current knowledge of the plant foliar and cellular uptake of dsRNA molecules. We will also identify major barriers to uptake, including leaf morphological features as well as environmental factors, and address methods to overcome these barriers.
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12
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Noar RD, Thomas E, Daub ME. Genetic Characteristics and Metabolic Interactions between Pseudocercospora fijiensis and Banana: Progress toward Controlling Black Sigatoka. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11070948. [PMID: 35406928 PMCID: PMC9002641 DOI: 10.3390/plants11070948] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/23/2022] [Accepted: 03/25/2022] [Indexed: 05/10/2023]
Abstract
The international importance of banana and severity of black Sigatoka disease have led to extensive investigations into the genetic characteristics and metabolic interactions between the Dothideomycete Pseudocercospora fijiensis and its banana host. P. fijiensis was shown to have a greatly expanded genome compared to other Dothideomycetes, due to the proliferation of retrotransposons. Genome analysis suggests the presence of dispensable chromosomes that may aid in fungal adaptation as well as pathogenicity. Genomic research has led to the characterization of genes and metabolic pathways involved in pathogenicity, including: secondary metabolism genes such as PKS10-2, genes for mitogen-activated protein kinases such as Fus3 and Slt2, and genes for cell wall proteins such as glucosyl phosphatidylinositol (GPI) and glycophospholipid surface (Gas) proteins. Studies conducted on resistance mechanisms in banana have documented the role of jasmonic acid and ethylene pathways. With the development of banana transformation protocols, strategies for engineering resistance include transgenes expressing antimicrobial peptides or hydrolytic enzymes as well as host-induced gene silencing (HIGS) targeting pathogenicity genes. Pseudocercospora fijiensis has been identified as having high evolutionary potential, given its large genome size, ability to reproduce both sexually and asexually, and long-distance spore dispersal. Thus, multiple control measures are needed for the sustainable control of black Sigatoka disease.
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Affiliation(s)
- Roslyn D. Noar
- NSF Center for Integrated Pest Management, North Carolina State University, Raleigh, NC 27606, USA
- Correspondence:
| | - Elizabeth Thomas
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA; (E.T.); (M.E.D.)
| | - Margaret E. Daub
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA; (E.T.); (M.E.D.)
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13
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Exploring the Effectiveness and Durability of Trans-Kingdom Silencing of Fungal Genes in the Vascular Pathogen Verticillium dahliae. Int J Mol Sci 2022; 23:ijms23052742. [PMID: 35269884 PMCID: PMC8910871 DOI: 10.3390/ijms23052742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 02/25/2022] [Accepted: 02/26/2022] [Indexed: 02/04/2023] Open
Abstract
Host-induced gene silencing (HIGS) based on trans-kingdom RNA interference (RNAi) has been successfully exploited to engineer host resistance to pests and pathogens, including fungi and oomycetes. However, revealing the mechanisms underlying trans-kingdom RNAi between hosts and pathogens lags behind applications. The effectiveness and durability of trans-kingdom silencing of pathogenic genes are uncharacterized. In this study, using our transgenic 35S-VdH1i cotton plants in which dsVdH1-derived small RNAs (siVdH1) accumulated, small RNA sequencing analysis revealed that siVdH1s exclusively occur within the double-stranded (ds)VdH1 region, and no transitive siRNAs were produced beyond this region in recovered hyphae of Verticillium dahliae (V. dahliae). Accordingly, we found that VdH1 silencing was reduced over time in recovered hyphae cultured in vitro, inferring that once the fungus got rid of the 35S-VdH1i cotton plants would gradually regain their pathogenicity. To explore whether continually exporting dsRNAs/siRNAs from transgenic plants into recipient fungal cells guaranteed the effectiveness and stability of HIGS, we created GFP/RFP double-labeled V. dahliae and transgenic Arabidopsis expressing dsGFP (35S-GFPi plants). Confocal images visually demonstrate the efficient silencing of GFP in V. dahliae that colonized host vascular tissues. Taken together, our results demonstrate that HIGS effectively triggers long-lasting trans-kingdom RNAi during plant vasculature V. dahliae interactions, despite no amplification or transitivity of RNAi being noted in this soil-borne fungal pathogen.
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14
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Piombo E, Vetukuri RR, Broberg A, Kalyandurg PB, Kushwaha S, Funck Jensen D, Karlsson M, Dubey M. Role of Dicer-Dependent RNA Interference in Regulating Mycoparasitic Interactions. Microbiol Spectr 2021; 9:e0109921. [PMID: 34549988 PMCID: PMC8557909 DOI: 10.1128/spectrum.01099-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 08/11/2021] [Indexed: 12/17/2022] Open
Abstract
Dicer-like proteins (DCLs) play a vital role in RNA interference (RNAi), by cleaving RNA filament into small RNAs. Although DCL-mediated RNAi can regulate interspecific communication between pathogenic/mutualistic organisms and their hosts, its role in mycoparasitic interactions is yet to be investigated. In this study, we deleted dcl genes in the mycoparasitic fungus Clonostachys rosea and characterize the functions of DCL-dependent RNAi in mycoparasitism. Deletion of dcl2 resulted in a mutant with reduced secondary metabolite production, antagonism toward the plant-pathogenic fungus Botrytis cinerea, and reduced ability to control Fusarium foot rot disease on wheat, caused by Fusarium graminearum. Transcriptome sequencing of the in vitro interaction between the C. rosea Δdcl2 strain and B. cinerea or F. graminearum identified the downregulation of genes coding for transcription factors, membrane transporters, hydrolytic enzymes, and secondary metabolites biosynthesis enzymes putatively involved in antagonistic interactions, in comparison with the C. rosea wild-type interaction. A total of 61 putative novel microRNA-like RNAs (milRNAs) were identified in C. rosea, and 11 were downregulated in the Δdcl2 mutant. In addition to putative endogenous gene targets, these milRNAs were predicted to target B. cinerea and F. graminearum virulence factor genes, which showed an increased expression during interaction with the Δdcl2 mutant incapable of producing the targeting milRNAs. In summary, this study constitutes the first step in elucidating the role of RNAi in mycoparasitic interactions, with important implications for biological control of plant diseases, and poses the base for future studies focusing on the role of cross-species RNAi regulating mycoparasitic interactions. IMPORTANCE Small RNAs mediated RNA interference (RNAi) known to regulate several biological processes. Dicer-like endoribonucleases (DCLs) play a vital role in the RNAi pathway by generating sRNAs. In this study, we investigated a role of DCL-mediated RNAi in interference interactions between mycoparasitic fungus Clonostachys rosea and the two fungal pathogens Botrytis cinerea and Fusarium graminearum (here called mycohosts). We found that the dcl mutants were not able to produce 11 sRNAs predicted to finetune the regulatory network of genes known to be involved in production of hydrolytic enzymes, antifungal compounds, and membrane transporters needed for antagonistic action of C. rosea. We also found C. rosea sRNAs putatively targeting known virulence factors in the mycohosts, indicating RNAi-mediated cross-species communication. Our study expanded the understanding of underlying mechanisms of cross-species communication during interference interactions and poses a base for future works studying the role of DCL-based cross-species RNAi in fungal interactions.
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Affiliation(s)
- Edoardo Piombo
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ramesh R. Vetukuri
- Department of Plant Breeding, Horticum, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Anders Broberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Pruthvi B. Kalyandurg
- Department of Plant Breeding, Horticum, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Sandeep Kushwaha
- Department of Plant Breeding, Horticum, Swedish University of Agricultural Sciences, Lomma, Sweden
- National Institute of Animal Biotechnology, Hyderabad, Telangana, India
| | - Dan Funck Jensen
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Magnus Karlsson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Mukesh Dubey
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Kwon S, Rupp O, Brachmann A, Blum CF, Kraege A, Goesmann A, Feldbrügge M. mRNA Inventory of Extracellular Vesicles from Ustilago maydis. J Fungi (Basel) 2021; 7:jof7070562. [PMID: 34356940 PMCID: PMC8306574 DOI: 10.3390/jof7070562] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/02/2021] [Accepted: 07/07/2021] [Indexed: 01/08/2023] Open
Abstract
Extracellular vesicles (EVs) can transfer diverse RNA cargo for intercellular communication. EV-associated RNAs have been found in diverse fungi and were proposed to be relevant for pathogenesis in animal hosts. In plant-pathogen interactions, small RNAs are exchanged in a cross-kingdom RNAi warfare and EVs were considered to be a delivery mechanism. To extend the search for EV-associated molecules involved in plant-pathogen communication, we have characterised the repertoire of EV-associated mRNAs secreted by the maize smut pathogen, Ustilago maydis. For this initial survey, we examined EV-enriched fractions from axenic filamentous cultures that mimic infectious hyphae. EV-associated RNAs were resistant to degradation by RNases and the presence of intact mRNAs was evident. The set of mRNAs enriched inside EVs relative to the fungal cells are functionally distinct from those that are depleted from EVs. mRNAs encoding metabolic enzymes are particularly enriched. Intriguingly, mRNAs of some known effectors and other proteins linked to virulence were also found in EVs. Furthermore, several mRNAs enriched in EVs are also upregulated during infection, suggesting that EV-associated mRNAs may participate in plant-pathogen interactions.
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Affiliation(s)
- Seomun Kwon
- Institute for Microbiology, Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (S.K.); (A.K.)
| | - Oliver Rupp
- Bioinformatics and Systems Biology, Justus-Liebig-Universität, 35392 Giessen, Germany; (O.R.); (A.G.)
| | - Andreas Brachmann
- Biocenter of the LMU Munich, Genetics Section, Grosshaderner Str. 2-4, 82152 Planegg-Martinsried, Germany;
| | - Christopher Frederik Blum
- Institute for Mathematical Modelling of Biological Systems, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
| | - Anton Kraege
- Institute for Microbiology, Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (S.K.); (A.K.)
| | - Alexander Goesmann
- Bioinformatics and Systems Biology, Justus-Liebig-Universität, 35392 Giessen, Germany; (O.R.); (A.G.)
| | - Michael Feldbrügge
- Institute for Microbiology, Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (S.K.); (A.K.)
- Correspondence: ; Tel.: +49-211-81-14720
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Habig M, Schotanus K, Hufnagel K, Happel P, Stukenbrock EH. Ago1 Affects the Virulence of the Fungal Plant Pathogen Zymoseptoria tritici. Genes (Basel) 2021; 12:1011. [PMID: 34208898 PMCID: PMC8303167 DOI: 10.3390/genes12071011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/23/2021] [Accepted: 06/28/2021] [Indexed: 12/04/2022] Open
Abstract
In host-pathogen interactions RNA interference (RNAi) has emerged as a pivotal mechanism to modify both, the immune responses of the host as well as the pathogenicity and virulence of the pathogen. In addition, in some fungi RNAi is also known to affect chromosome biology via its effect on chromatin conformation. Previous studies reported no effect of the RNAi machinery on the virulence of the fungal plant pathogen Zymoseptoria tritici however the role of RNAi is still poorly understood in this species. Herein, we elucidate whether the RNAi machinery is conserved within the genus Zymoseptoria. Moreover, we conduct functional analyses of Argonaute and Dicer-like proteins and test if the RNAi machinery affects chromosome stability. We show that the RNAi machinery is conserved among closely related Zymoseptoria species while an exceptional pattern of allelic diversity was possibly caused by introgression. The deletion of Ago1 reduced the ability of the fungus to produce asexual propagules in planta in a quantitative matter. Chromosome stability of the accessory chromosome of Z. tritici was not prominently affected by the RNAi machinery. These results indicate, in contrast to previous finding, a role of the RNAi pathway during host infection, but not in the stability of accessory chromosomes in Z. tritici.
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Affiliation(s)
- Michael Habig
- Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 1-11, 24118 Kiel, Germany; (M.H.); (K.S.); (K.H.)
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Klaas Schotanus
- Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 1-11, 24118 Kiel, Germany; (M.H.); (K.S.); (K.H.)
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Kim Hufnagel
- Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 1-11, 24118 Kiel, Germany; (M.H.); (K.S.); (K.H.)
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Petra Happel
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany;
| | - Eva H. Stukenbrock
- Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 1-11, 24118 Kiel, Germany; (M.H.); (K.S.); (K.H.)
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
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Šečić E, Kogel KH. Requirements for fungal uptake of dsRNA and gene silencing in RNAi-based crop protection strategies. Curr Opin Biotechnol 2021; 70:136-142. [PMID: 34000482 DOI: 10.1016/j.copbio.2021.04.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/08/2021] [Accepted: 04/09/2021] [Indexed: 02/01/2023]
Abstract
Growing evidence indicates that RNAi is an effective control strategy for agronomically important fungi. To implement RNAi-based crop protection strategies, dsRNA molecules are either sprayed on foliage or generated by genetically engineered plants. Here, we summarize current knowledge of the mechanisms governing dsRNA uptake and RNAi-mediated gene silencing in fungi, as well as the factors that influence these phenomena. Of primary importance is dsRNA design, as identifying an appropriate gene for silencing and determining which region of the gene to target are critical for maximizing efficiency. Strategies for enhancing dsRNA uptake, potentially by using formulations and/or carriers that prevent dsRNA degradation by (a)biotic factors and possibly facilitate translocation, also are a key consideration. Finally, determining whether the fungal pathogen of interest contains a functional RNAi machinery is a major consideration. Integrated experimental confirmation of these important factors is necessary for the successful development of crop protection strategies against fungal pathogens.
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Affiliation(s)
- Ena Šečić
- Institute of Phytopathology, Centre for BioSystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26, 35392 Giessen, Germany
| | - Karl-Heinz Kogel
- Institute of Phytopathology, Centre for BioSystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26, 35392 Giessen, Germany.
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RNA Interference Strategies for Future Management of Plant Pathogenic Fungi: Prospects and Challenges. PLANTS 2021; 10:plants10040650. [PMID: 33805521 PMCID: PMC8067263 DOI: 10.3390/plants10040650] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/11/2022]
Abstract
Plant pathogenic fungi are the largest group of disease-causing agents on crop plants and represent a persistent and significant threat to agriculture worldwide. Conventional approaches based on the use of pesticides raise social concern for the impact on the environment and human health and alternative control methods are urgently needed. The rapid improvement and extensive implementation of RNA interference (RNAi) technology for various model and non-model organisms has provided the initial framework to adapt this post-transcriptional gene silencing technology for the management of fungal pathogens. Recent studies showed that the exogenous application of double-stranded RNA (dsRNA) molecules on plants targeting fungal growth and virulence-related genes provided disease attenuation of pathogens like Botrytis cinerea, Sclerotinia sclerotiorum and Fusarium graminearum in different hosts. Such results highlight that the exogenous RNAi holds great potential for RNAi-mediated plant pathogenic fungal disease control. Production of dsRNA can be possible by using either in-vitro or in-vivo synthesis. In this review, we describe exogenous RNAi involved in plant pathogenic fungi and discuss dsRNA production, formulation, and RNAi delivery methods. Potential challenges that are faced while developing a RNAi strategy for fungal pathogens, such as off-target and epigenetic effects, with their possible solutions are also discussed.
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Role of Non-coding RNAs in Fungal Pathogenesis and Antifungal Drug Responses. CURRENT CLINICAL MICROBIOLOGY REPORTS 2020. [DOI: 10.1007/s40588-020-00151-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abstract
Purpose of Review
Non-coding RNAs (ncRNAs), including regulatory small RNAs (sRNAs) and long non-coding RNAs (lncRNAs), constitute a significant part of eukaryotic genomes; however, their roles in fungi are just starting to emerge. ncRNAs have been shown to regulate gene expression in response to varying environmental conditions (like stress) and response to chemicals, including antifungal drugs. In this review, I highlighted recent studies focusing on the functional roles of ncRNAs in pathogenic fungi.
Recent Findings
Emerging evidence suggests sRNAs (small RNAs) and lncRNAs (long non-coding RNAs) play an important role in fungal pathogenesis and antifungal drug response. Their roles include posttranscriptional gene silencing, histone modification, and chromatin remodeling. Fungal pathogens utilize RNA interference (RNAi) mechanisms to regulate pathogenesis-related genes and can also transfer sRNAs inside the host to suppress host immunity genes to increase virulence. Hosts can also transfer sRNAs to induce RNAi in fungal pathogens to reduce virulence. Additionally, sRNAs and lncRNAs also regulate gene expression in response to antifungal drugs increasing resistance (and possibly tolerance) to drugs.
Summary
Herein, I discuss what is known about ncRNAs in fungal pathogenesis and antifungal drug responses. Advancements in genomic technologies will help identify the ncRNA repertoire in fungal pathogens, and functional studies will elucidate their mechanisms. This will advance our understanding of host-fungal interactions and potentially help develop better treatment strategies.
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20
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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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21
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Comprehensive profiling of codon usage signatures and codon context variations in the genus Ustilago. World J Microbiol Biotechnol 2019; 35:118. [DOI: 10.1007/s11274-019-2693-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 07/07/2019] [Indexed: 02/02/2023]
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22
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Kusch S, Frantzeskakis L, Thieron H, Panstruga R. Small RNAs from cereal powdery mildew pathogens may target host plant genes. Fungal Biol 2018; 122:1050-1063. [PMID: 30342621 DOI: 10.1016/j.funbio.2018.08.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/25/2018] [Accepted: 08/28/2018] [Indexed: 12/24/2022]
Abstract
Small RNAs (sRNAs) play a key role in eukaryotic gene regulation, for example by gene silencing via RNA interference (RNAi). The biogenesis of sRNAs depends on proteins that are generally conserved in all eukaryotic lineages, yet some species that lack part or all the components of the mechanism exist. Here we explored the presence of the RNAi machinery and its expression as well as the occurrence of sRNA candidates and their putative endogenous as well as host targets in phytopathogenic powdery mildew fungi. We focused on the species Blumeria graminis, which occurs in various specialized forms (formae speciales) that each have a strictly limited host range. B. graminis f. sp. hordei and B. graminis f. sp. tritici, colonizing barley and wheat, respectively, have genomes that are characterized by extensive gene loss. Nonetheless, we find that the RNAi machinery appears to be largely complete and expressed during infection. sRNA sequencing data enabled the identification of putative sRNAs in both pathogens. While a considerable part of the sRNA candidates have predicted target sites in endogenous genes and transposable elements, a small proportion appears to have targets in planta, suggesting potential cross-kingdom RNA transfer between powdery mildew fungi and their respective plant hosts.
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Affiliation(s)
- Stefan Kusch
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, D-52056 Aachen, Germany.
| | - Lamprinos Frantzeskakis
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, D-52056 Aachen, Germany.
| | - Hannah Thieron
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, D-52056 Aachen, Germany.
| | - Ralph Panstruga
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, D-52056 Aachen, Germany.
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Torres-Martínez S, Ruiz-Vázquez RM. The RNAi Universe in Fungi: A Varied Landscape of Small RNAs and Biological Functions. Annu Rev Microbiol 2017; 71:371-391. [PMID: 28657888 DOI: 10.1146/annurev-micro-090816-093352] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNA interference (RNAi) is a conserved eukaryotic mechanism that uses small RNA molecules to suppress gene expression through sequence-specific messenger RNA degradation, translational repression, or transcriptional inhibition. In filamentous fungi, the protective function of RNAi in the maintenance of genome integrity is well known. However, knowledge of the regulatory role of RNAi in fungi has had to wait until the recent identification of different endogenous small RNA classes, which are generated by distinct RNAi pathways. In addition, RNAi research on new fungal models has uncovered the role of small RNAs and RNAi pathways in the regulation of diverse biological functions. In this review, we give an up-to-date overview of the different classes of small RNAs and RNAi pathways in fungi and their roles in the defense of genome integrity and regulation of fungal physiology and development, as well as in the interaction of fungi with biotic and abiotic environments.
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Wang WX, Zhu TH, Li KL, Chen LF, Lai FX, Fu Q. Molecular characterization, expression analysis and RNAi knock-down of elongation factor 1α and 1γ from Nilaparvata lugens and its yeast-like symbiont. BULLETIN OF ENTOMOLOGICAL RESEARCH 2017; 107:303-312. [PMID: 27809951 DOI: 10.1017/s0007485316000882] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In the present paper, four cDNAs encoding the alpha and gamma subunits of elongation factor 1 (EF-1) were cloned and sequenced from Nilaparvata lugens, named NlEF-1α, NlEF-1γ, and its yeast-like symbiont (YLS), named YsEF-1α and YsEF-1γ, respectively. Comparisons with sequences from other species indicated a greater conservation for EF-1α than for EF-1γ. NlEF-1α has two identical copies. The deduced amino acid sequence homology of NlEF-1α and NlEF-1γ is 96 and 64%, respectively, compared with Homalodisca vitripennis and Locusta migratoria. The deduced amino acid sequence homology of YsEF-1α and YsEF-1γ is 96 and 74%, respectively, compared with Metarhizium anisopliae and Ophiocordyceps sinensis. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis revealed that the expression level of NlEF-1α and NlEF-1γ mRNA in hemolymph, ovary, fat body and salivary glands were higher than the midgut and leg tissue. YsEF-1α and YsEF-1γ was highly expressed in fat body. The expression level of NlEF-1α was higher than that of NlEF-1γ. Through RNA interference (RNAi) of the two genes, the mortality of nymph reached 92.2% at the 11th day after treatment and the ovarian development was severely hindered. The RT-qPCR analysis verified the correlation between mortality, sterility and the down-regulation of the target genes. The expression and synthesis of vitellogenin (Vg) protein in insects injected with NlEF-1α and NlEF-1γ double-stranded RNA (dsRNA) was significantly lower than control groups. Attempts to knockdown the YsEF-1 genes in the YLS was unsuccessful. However, the phenotype of N. lugens injected with YsEF-1α dsRNA was the same as that injected with NlEF-1α dsRNA, possibly due to the high similarity (up to 71.9%) in the nucleotide sequences between NlEF-1α and YsEF-1α. We demonstrated that partial silencing of NlEF-1α and NlEF-1γ genes caused lethal and sterility effect on N. lugens. NlEF-1γ shares low identity with that of other insects and therefore it could be a potential target for RNAi-based pest management.
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Affiliation(s)
- W X Wang
- State Key Laboratory of Rice Biology,China National Rice Research Institute,Tiyuchang Road 359, Hangzhou, Zhejiang, 310006,People's Republic of China
| | - T H Zhu
- College of Biological and Environmental Engineering,Zhejiang University of Technology,Chaowang Road,Hangzhou,Zhejiang, 310014,People's Republic of China
| | - K L Li
- State Key Laboratory of Rice Biology,China National Rice Research Institute,Tiyuchang Road 359, Hangzhou, Zhejiang, 310006,People's Republic of China
| | - L F Chen
- State Key Laboratory of Rice Biology,China National Rice Research Institute,Tiyuchang Road 359, Hangzhou, Zhejiang, 310006,People's Republic of China
| | - F X Lai
- State Key Laboratory of Rice Biology,China National Rice Research Institute,Tiyuchang Road 359, Hangzhou, Zhejiang, 310006,People's Republic of China
| | - Q Fu
- State Key Laboratory of Rice Biology,China National Rice Research Institute,Tiyuchang Road 359, Hangzhou, Zhejiang, 310006,People's Republic of China
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Donaldson ME, Ostrowski LA, Goulet KM, Saville BJ. Transcriptome analysis of smut fungi reveals widespread intergenic transcription and conserved antisense transcript expression. BMC Genomics 2017; 18:340. [PMID: 28464849 PMCID: PMC5414199 DOI: 10.1186/s12864-017-3720-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/25/2017] [Indexed: 12/12/2022] Open
Abstract
Background Biotrophic fungal plant pathogens cause billions of dollars in losses to North American crops annually. The model for functional investigation of these fungi is Ustilago maydis. Its 20.5 Mb annotated genome sequence has been an excellent resource for investigating biotrophic plant pathogenesis. Expressed-sequence tag libraries and microarray hybridizations have provided insight regarding the type of transcripts produced by U. maydis but these analyses were not comprehensive and there were insufficient data for transcriptome comparison to other smut fungi. To improve transcriptome annotation and enable comparative analyses, comprehensive strand-specific RNA-seq was performed on cell-types of three related smut species: U. maydis (common smut of corn), Ustilago hordei (covered smut of barley), and Sporisorium reilianum (head smut of corn). Results In total, >1 billion paired-end sequence reads were obtained from haploid cell, dikaryon and teliospore RNA of U. maydis, haploid cell RNA of U. hordei, and haploid and dikaryon cell RNA of S. reilianum. The sequences were assembled into transfrags using Trinity, and updated gene models were created using PASA and categorized with Cufflinks Cuffcompare. Representative genes that were predicted for the first time with these RNA-seq analyses and genes with novel annotation features were independently assessed by reverse transcriptase PCR. The analyses indicate hundreds more predicted proteins, relative to the previous genome annotation, could be produced by U. maydis from altered transcript forms, and that the number of non-coding RNAs produced, including transcribed intergenic sequences and natural antisense transcripts, approximately equals the number of mRNAs. This high representation of non-coding RNAs appears to be a conserved feature of the smut fungi regardless of whether they have RNA interference machinery. Approximately 50% of the identified NATs were conserved among the smut fungi. Conclusions Overall, these analyses revealed: 1) smut genomes encode a number of transcriptional units that is twice the number of annotated protein-coding genes, 2) a small number of intergenic transcripts may encode proteins with characteristics of fungal effectors, 3) the vast majority of intergenic and antisense transcripts do not contain ORFs, 4) a large proportion of the identified antisense transcripts were detected at orthologous loci among the smut fungi, and 5) there is an enrichment of functional categories among orthologous loci that suggests antisense RNAs could have a genome-wide, non-RNAi-mediated, influence on gene expression in smut fungi. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3720-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael E Donaldson
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, K9L 0G2, ON, Canada
| | - Lauren A Ostrowski
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, K9L 0G2, ON, Canada.,Present Address: Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, M5S 1A8, ON, Canada
| | - Kristi M Goulet
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, K9L 0G2, ON, Canada
| | - Barry J Saville
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, K9L 0G2, ON, Canada. .,Forensic Science Program, Trent University, Peterborough, K9L 0G2, ON, Canada.
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Ostrowski LA, Saville BJ. Natural antisense transcripts are linked to the modulation of mitochondrial function and teliospore dormancy in Ustilago maydis. Mol Microbiol 2017; 103:745-763. [PMID: 27888605 DOI: 10.1111/mmi.13587] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 11/22/2016] [Accepted: 11/22/2016] [Indexed: 01/30/2023]
Abstract
The basidiomycete smut fungus Ustilago maydis causes common smut of corn. This disease is spread through the production of teliospores, which are thick-walled dormant structures characterized by low rates of respiration and metabolism. Teliospores are formed when the fungus grows within the plant, and the morphological steps involved in their formation have been described, but the molecular events leading to dormancy are not known. In U. maydis, natural antisense transcripts (NATs) can function to alter gene expression and many NATs have increased levels in the teliospore. One such NAT is as-ssm1 which is complementary to the gene for the mitochondrial seryl-tRNA synthetase (ssm1), an enzyme important to mitochondrial function. The disruption of ssm1 leads to cell lysis, indicating it is also essential for cellular viability. To assess the function of as-ssm1, it was ectopically expressed in haploid cells, where it is not normally present. This expression led to reductions in growth rate, virulence, mitochondrial membrane potential and oxygen consumption. It also resulted in the formation of as-ssm1/ssm1 double-stranded RNA and increased ssm1 transcript levels, but no change in Ssm1 protein levels was detected. Together, these findings suggest a role for as-ssm1 in facilitating teliospore dormancy through dsRNA formation and reduction of mitochondrial function.
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Affiliation(s)
- Lauren A Ostrowski
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada, K9L 0G2
| | - Barry J Saville
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada, K9L 0G2.,Forensic Science Program, Trent University, Peterborough, ON, Canada, K9L 0G2
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McTaggart AR, Shivas RG, Boekhout T, Oberwinkler F, Vánky K, Pennycook SR, Begerow D. Mycosarcoma ( Ustilaginaceae), a resurrected generic name for corn smut ( Ustilago maydis) and its close relatives with hypertrophied, tubular sori. IMA Fungus 2016; 7:309-315. [PMID: 27990337 PMCID: PMC5159601 DOI: 10.5598/imafungus.2016.07.02.10] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 11/18/2016] [Indexed: 01/13/2023] Open
Abstract
Ustilago is a polyphyletic genus of smut fungi found mainly on Poaceae. The development of a taxonomy that reflects phylogeny requires subdivision of Ustilago into smaller monophyletic genera. Several separate systematic analyses have determined that Macalpinomyces mackinlayi, M. tubiformis, Tolyposporella pachycarpa, Ustilago bouriquetii and U. maydis, occupy a unique phylogenetic position within the Ustilaginaceae. A previously introduced monotypic generic name typified by U. maydis, Mycosarcoma, is available to accommodate these species, which resolves one component of polyphyly for Ustilagos.lat. in Ustilaginaceae. An emended description of Mycosarcoma is provided to reflect the morphological synapomorphies of this monophyletic group. A specimen of Ustilago maydis that has had its genome sequenced is designated as a neotype for this species. Taxonomic stability will further be provided by a forthcoming proposal to conserve the name Uredo maydis over Lycoperdon zeae, which has priority by date, in order to preserve the well-known epithet maydis.
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Affiliation(s)
- Alistair R McTaggart
- Department of Microbiology and Plant Pathology, Tree Protection Co-operative Programme (TPCP), Forestry and Agricultural Biotechnology Institute (FABI), Private Bag X20, University of Pretoria, Pretoria, 0028, South Africa; Plant Biosecurity Cooperative Research Centre, LPO Box 5012, Bruce 2617, Australia
| | - Roger G Shivas
- Plant Pathology Herbarium, Biosecurity Queensland, Department of Agriculture and Fisheries, GPO Box 267, Brisbane 4001, Queensland, Australia
| | - Teun Boekhout
- CBS-KNAW Fungal Biodiversity (CBS-KNAW), Utrecht, The Netherlands; Institute of Biodiversity and Ecosystems Dynamics (IBED), University of Amsterdam, Amsterdam
| | - Franz Oberwinkler
- Eberhard-Karls Universität, Auf der Morgenstelle 5, D-72076 Tübingen, Germany
| | - Kálmán Vánky
- Herbarium Ustilaginales Vánky (HUV), Gabriel-Biel-Str. 5, D-72076 Tübingen, Germany
| | - Shaun R Pennycook
- Landcare Research Manaaki Whenua, Private Bag 92170, Auckland 1142, New Zealand
| | - Dominik Begerow
- Ruhr-Universität Bochum, Geobotanik, ND 03/174, Universitätsstr. 150, 44801 Bochum, Germany
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Chaloner T, van Kan JAL, Grant-Downton RT. RNA 'Information Warfare' in Pathogenic and Mutualistic Interactions. TRENDS IN PLANT SCIENCE 2016; 21:738-748. [PMID: 27318950 DOI: 10.1016/j.tplants.2016.05.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 05/13/2016] [Accepted: 05/19/2016] [Indexed: 05/08/2023]
Abstract
Regulatory non-coding RNAs are emerging as key players in host-pathogen interactions. Small RNAs such as microRNAs are implicated in regulating plant transcripts involved in immunity and defence. Surprisingly, RNAs with silencing properties can be translocated from plant hosts to various invading pathogens and pests. Small RNAs are now confirmed virulence factors, with the first report of fungal RNAs that travel to host cells and hijack post-transcriptional regulatory machinery to suppress host defence. Here, we argue that trans-organism movement of RNAs represents a common mechanism of control in diverse interactions between plants and other eukaryotes. We suggest that extracellular vesicles are the key to such RNA movement events. Plant pathosystems serve as excellent experimental models to dissect RNA 'information warfare' and other RNA-mediated interactions.
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Affiliation(s)
- Thomas Chaloner
- The Queen's College, University of Oxford, High Street, Oxford, UK
| | - Jan A L van Kan
- Wageningen University, Laboratory of Phytopathology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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Gebert D, Rosenkranz D. RNA-based regulation of transposon expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 6:687-708. [DOI: 10.1002/wrna.1310] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/08/2015] [Accepted: 09/13/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Daniel Gebert
- Institute of Anthropology; Johannes Gutenberg University; Mainz Germany
| | - David Rosenkranz
- Institute of Anthropology; Johannes Gutenberg University; Mainz Germany
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Sharma R, Xia X, Riess K, Bauer R, Thines M. Comparative Genomics Including the Early-Diverging Smut Fungus Ceraceosorus bombacis Reveals Signatures of Parallel Evolution within Plant and Animal Pathogens of Fungi and Oomycetes. Genome Biol Evol 2015; 7:2781-98. [PMID: 26314305 PMCID: PMC4607519 DOI: 10.1093/gbe/evv162] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ceraceosorus bombacis is an early-diverging lineage of smut fungi and a pathogen of cotton trees (Bombax ceiba). To study the evolutionary genomics of smut fungi in comparison with other fungal and oomycete pathogens, the genome of C. bombacis was sequenced and comparative genomic analyses were performed. The genome of 26.09 Mb encodes for 8,024 proteins, of which 576 are putative-secreted effector proteins (PSEPs). Orthology analysis revealed 30 ortholog PSEPs among six Ustilaginomycotina genomes, the largest groups of which are lytic enzymes, such as aspartic peptidase and glycoside hydrolase. Positive selection analyses revealed the highest percentage of positively selected PSEPs in C. bombacis compared with other Ustilaginomycotina genomes. Metabolic pathway analyses revealed the absence of genes encoding for nitrite and nitrate reductase in the genome of the human skin pathogen Malassezia globosa, but these enzymes are present in the sequenced plant pathogens in smut fungi. Interestingly, these genes are also absent in cultivable oomycete animal pathogens, while nitrate reductase has been lost in cultivable oomycete plant pathogens. Similar patterns were also observed for obligate biotrophic and hemi-biotrophic fungal and oomycete pathogens. Furthermore, it was found that both fungal and oomycete animal pathogen genomes are lacking cutinases and pectinesterases. Overall, these findings highlight the parallel evolution of certain genomic traits, revealing potential common evolutionary trajectories among fungal and oomycete pathogens, shaping the pathogen genomes according to their lifestyle.
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Affiliation(s)
- Rahul Sharma
- Biodiversity and Climate Research Centre (BiK-F), Frankfurt (Main), Germany Department for Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe University, Frankfurt (Main), Germany Senckenberg Gesellschaft für Naturforschung, Frankfurt (Main), Germany Cluster for Integrative Fungal Research (IPF), Frankfurt (Main), Germany
| | - Xiaojuan Xia
- Biodiversity and Climate Research Centre (BiK-F), Frankfurt (Main), Germany Department for Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe University, Frankfurt (Main), Germany Senckenberg Gesellschaft für Naturforschung, Frankfurt (Main), Germany
| | - Kai Riess
- Plant Evolutionary Ecology, Institute of Evolution and Ecology, University of Tübingen, Germany
| | - Robert Bauer
- Plant Evolutionary Ecology, Institute of Evolution and Ecology, University of Tübingen, Germany
| | - Marco Thines
- Biodiversity and Climate Research Centre (BiK-F), Frankfurt (Main), Germany Department for Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe University, Frankfurt (Main), Germany Senckenberg Gesellschaft für Naturforschung, Frankfurt (Main), Germany Cluster for Integrative Fungal Research (IPF), Frankfurt (Main), Germany
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31
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Choi J, Kim KT, Jeon J, Wu J, Song H, Asiegbu FO, Lee YH. funRNA: a fungi-centered genomics platform for genes encoding key components of RNAi. BMC Genomics 2014; 15 Suppl 9:S14. [PMID: 25522231 PMCID: PMC4290597 DOI: 10.1186/1471-2164-15-s9-s14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND RNA interference (RNAi) is involved in genome defense as well as diverse cellular, developmental, and physiological processes. Key components of RNAi are Argonaute, Dicer, and RNA-dependent RNA polymerase (RdRP), which have been functionally characterized mainly in model organisms. The key components are believed to exist throughout eukaryotes; however, there is no systematic platform for archiving and dissecting these important gene families. In addition, few fungi have been studied to date, limiting our understanding of RNAi in fungi. Here we present funRNA http://funrna.riceblast.snu.ac.kr/, a fungal kingdom-wide comparative genomics platform for putative genes encoding Argonaute, Dicer, and RdRP. DESCRIPTION To identify and archive genes encoding the abovementioned key components, protein domain profiles were determined from reference sequences obtained from UniProtKB/SwissProt. The domain profiles were searched using fungal, metazoan, and plant genomes, as well as bacterial and archaeal genomes. 1,163, 442, and 678 genes encoding Argonaute, Dicer, and RdRP, respectively, were predicted. Based on the identification results, active site variation of Argonaute, diversification of Dicer, and sequence analysis of RdRP were discussed in a fungus-oriented manner. funRNA provides results from diverse bioinformatics programs and job submission forms for BLAST, BLASTMatrix, and ClustalW. Furthermore, sequence collections created in funRNA are synced with several gene family analysis portals and databases, offering further analysis opportunities. CONCLUSIONS funRNA provides identification results from a broad taxonomic range and diverse analysis functions, and could be used in diverse comparative and evolutionary studies. It could serve as a versatile genomics workbench for key components of RNAi.
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Affiliation(s)
- Jaeyoung Choi
- Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Korea
- Fungal Bioinformatics Laboratory, Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
| | - Ki-Tae Kim
- Fungal Bioinformatics Laboratory, Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
| | - Jongbum Jeon
- Fungal Bioinformatics Laboratory, Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
| | - Jiayao Wu
- Department of Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Hyeunjeong Song
- Fungal Bioinformatics Laboratory, Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
| | - Fred O Asiegbu
- Department of Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Yong-Hwan Lee
- Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Korea
- Fungal Bioinformatics Laboratory, Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
- Department of Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
- Center for Fungal Genetic Resources, Plant Genomics and Breeding Institute, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
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Perez-Nadales E, Nogueira MFA, Baldin C, Castanheira S, El Ghalid M, Grund E, Lengeler K, Marchegiani E, Mehrotra PV, Moretti M, Naik V, Oses-Ruiz M, Oskarsson T, Schäfer K, Wasserstrom L, Brakhage AA, Gow NAR, Kahmann R, Lebrun MH, Perez-Martin J, Di Pietro A, Talbot NJ, Toquin V, Walther A, Wendland J. Fungal model systems and the elucidation of pathogenicity determinants. Fungal Genet Biol 2014; 70:42-67. [PMID: 25011008 PMCID: PMC4161391 DOI: 10.1016/j.fgb.2014.06.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 06/23/2014] [Accepted: 06/25/2014] [Indexed: 12/05/2022]
Abstract
Fungi have the capacity to cause devastating diseases of both plants and animals, causing significant harvest losses that threaten food security and human mycoses with high mortality rates. As a consequence, there is a critical need to promote development of new antifungal drugs, which requires a comprehensive molecular knowledge of fungal pathogenesis. In this review, we critically evaluate current knowledge of seven fungal organisms used as major research models for fungal pathogenesis. These include pathogens of both animals and plants; Ashbya gossypii, Aspergillus fumigatus, Candida albicans, Fusarium oxysporum, Magnaporthe oryzae, Ustilago maydis and Zymoseptoria tritici. We present key insights into the virulence mechanisms deployed by each species and a comparative overview of key insights obtained from genomic analysis. We then consider current trends and future challenges associated with the study of fungal pathogenicity.
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Affiliation(s)
- Elena Perez-Nadales
- Department of Genetics, Edificio Gregor Mendel, Planta 1. Campus de Rabanales, University of Cordoba, 14071 Cordoba, Spain.
| | | | - Clara Baldin
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Beutembergstr. 11a, 07745 Jena, Germany; Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University Jena, Beutenbergstr. 11a, 07745 Jena, Germany
| | - Sónia Castanheira
- Instituto de Biología Funcional y GenómicaCSIC, Universidad de Salamanca, 37007 Salamanca, Spain
| | - Mennat El Ghalid
- Department of Genetics, Edificio Gregor Mendel, Planta 1. Campus de Rabanales, University of Cordoba, 14071 Cordoba, Spain
| | - Elisabeth Grund
- Functional Genomics of Plant Pathogenic Fungi, UMR 5240 CNRS-UCB-INSA-Bayer SAS, Bayer CropScience, 69263 Lyon, France
| | - Klaus Lengeler
- Carlsberg Laboratory, Department of Yeast Genetics, Gamle Carlsberg Vej 10, DK-1799, Copenhagen V, Denmark
| | - Elisabetta Marchegiani
- Evolution and Genomics of Plant Pathogen Interactions, UR 1290 INRA, BIOGER-CPP, Campus AgroParisTech, 78850 Thiverval-Grignon, France
| | - Pankaj Vinod Mehrotra
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Marino Moretti
- Max-Planck-Institute for Terrestrial Microbiology, Department of Organismic Interactions, Karl-von-Frisch-Strasse 10, D-35043 Marburg, Germany
| | - Vikram Naik
- Max-Planck-Institute for Terrestrial Microbiology, Department of Organismic Interactions, Karl-von-Frisch-Strasse 10, D-35043 Marburg, Germany
| | - Miriam Oses-Ruiz
- School of Biosciences, Geoffrey Pope Building, University of Exeter, Exeter EX4 4QD, UK
| | - Therese Oskarsson
- Carlsberg Laboratory, Department of Yeast Genetics, Gamle Carlsberg Vej 10, DK-1799, Copenhagen V, Denmark
| | - Katja Schäfer
- Department of Genetics, Edificio Gregor Mendel, Planta 1. Campus de Rabanales, University of Cordoba, 14071 Cordoba, Spain
| | - Lisa Wasserstrom
- Carlsberg Laboratory, Department of Yeast Genetics, Gamle Carlsberg Vej 10, DK-1799, Copenhagen V, Denmark
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Beutembergstr. 11a, 07745 Jena, Germany; Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University Jena, Beutenbergstr. 11a, 07745 Jena, Germany
| | - Neil A R Gow
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Regine Kahmann
- Max-Planck-Institute for Terrestrial Microbiology, Department of Organismic Interactions, Karl-von-Frisch-Strasse 10, D-35043 Marburg, Germany
| | - Marc-Henri Lebrun
- Evolution and Genomics of Plant Pathogen Interactions, UR 1290 INRA, BIOGER-CPP, Campus AgroParisTech, 78850 Thiverval-Grignon, France
| | - José Perez-Martin
- Instituto de Biología Funcional y GenómicaCSIC, Universidad de Salamanca, 37007 Salamanca, Spain
| | - Antonio Di Pietro
- Department of Genetics, Edificio Gregor Mendel, Planta 1. Campus de Rabanales, University of Cordoba, 14071 Cordoba, Spain
| | - Nicholas J Talbot
- School of Biosciences, Geoffrey Pope Building, University of Exeter, Exeter EX4 4QD, UK
| | - Valerie Toquin
- Biochemistry Department, Bayer SAS, Bayer CropScience, CRLD, 69263 Lyon, France
| | - Andrea Walther
- Carlsberg Laboratory, Department of Yeast Genetics, Gamle Carlsberg Vej 10, DK-1799, Copenhagen V, Denmark
| | - Jürgen Wendland
- Carlsberg Laboratory, Department of Yeast Genetics, Gamle Carlsberg Vej 10, DK-1799, Copenhagen V, Denmark
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Exploring microRNA-like small RNAs in the filamentous fungus Fusarium oxysporum. PLoS One 2014; 9:e104956. [PMID: 25141304 PMCID: PMC4139310 DOI: 10.1371/journal.pone.0104956] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 07/12/2014] [Indexed: 12/17/2022] Open
Abstract
RNA silencing such as quelling and meiotic silencing by unpaired DNA (MSUD) and several other classes of special small RNAs have been discovered in filamentous fungi recently. More than four different mechanisms of microRNA-like RNAs (milRNAs) production have been illustrated in the model fungus Neurospora crassa including a dicer-independent pathway. To date, very little work focusing on small RNAs in fungi has been reported and no universal or particular characteristic of milRNAs were defined clearly. In this study, small RNA and degradome libraries were constructed and subsequently deep sequenced for investigating milRNAs and their potential cleavage targets on the genome level in the filamentous fungus F. oxysporum f. sp. lycopersici. As a result, there is no intersection of conserved miRNAs found by BLASTing against the miRBase. Further analysis showed that the small RNA population of F. oxysporum shared many common features with the small RNAs from N. crassa and other fungi. According to the known standards of miRNA prediction in plants and animals, milRNA candidates from 8 families (comprising 19 members) were screened out and identified. However, none of them could trigger target cleavage based on the degradome data. Moreover, most major signals of cleavage in transcripts could not match appropriate complementary small RNAs, suggesting that other predominant modes for milRNA-mediated gene regulation could exist in F. oxysporum. In addition, the PAREsnip program was utilized for comprehensive analysis and 3 families of small RNAs leading to transcript cleavage were experimentally validated. Altogether, our findings provided valuable information and important hints for better understanding the functions of the small RNAs and milRNAs in the fungal kingdom.
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An immunity-triggering effector from the Barley smut fungus Ustilago hordei resides in an Ustilaginaceae-specific cluster bearing signs of transposable element-assisted evolution. PLoS Pathog 2014; 10:e1004223. [PMID: 24992661 PMCID: PMC4081816 DOI: 10.1371/journal.ppat.1004223] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 05/15/2014] [Indexed: 11/19/2022] Open
Abstract
The basidiomycete smut fungus Ustilago hordei was previously shown to comprise isolates that are avirulent on various barley host cultivars. Through genetic crosses we had revealed that a dominant avirulence locus UhAvr1 which triggers immunity in barley cultivar Hannchen harboring resistance gene Ruh1, resided within an 80-kb region. DNA sequence analysis of this genetically delimited region uncovered the presence of 7 candidate secreted effector proteins. Sequence comparison of their coding sequences among virulent and avirulent parental and field isolates could not distinguish UhAvr1 candidates. Systematic deletion and complementation analyses revealed that UhAvr1 is UHOR_10022 which codes for a small effector protein of 171 amino acids with a predicted 19 amino acid signal peptide. Virulence in the parental isolate is caused by the insertion of a fragment of 5.5 kb with similarity to a common U. hordei transposable element (TE), interrupting the promoter of UhAvr1 and thereby changing expression and hence recognition of UhAVR1p. This rearrangement is likely caused by activities of TEs and variation is seen among isolates. Using GFP-chimeric constructs we show that UhAvr1 is induced only in mated dikaryotic hyphae upon sensing and infecting barley coleoptile cells. When infecting Hannchen, UhAVR1p causes local callose deposition and the production of reactive oxygen species and necrosis indicative of the immune response. UhAvr1 does not contribute significantly to overall virulence. UhAvr1 is located in a cluster of ten effectors with several paralogs and over 50% of TEs. This cluster is syntenous with clusters in closely-related U. maydis and Sporisorium reilianum. In these corn-infecting species, these clusters harbor however more and further diversified homologous effector families but very few TEs. This increased variability may have resulted from past selection pressure by resistance genes since U. maydis is not known to trigger immunity in its corn host.
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35
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Burroughs AM, Ando Y, Aravind L. New perspectives on the diversification of the RNA interference system: insights from comparative genomics and small RNA sequencing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 5:141-81. [PMID: 24311560 DOI: 10.1002/wrna.1210] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/03/2013] [Accepted: 11/01/2013] [Indexed: 12/19/2022]
Abstract
Our understanding of the pervasive involvement of small RNAs in regulating diverse biological processes has been greatly augmented by recent application of deep-sequencing technologies to small RNA across diverse eukaryotes. We review the currently known small RNA classes and place them in context of the reconstructed evolutionary history of the RNA interference (RNAi) protein machinery. This synthesis indicates that the earliest versions of eukaryotic RNAi systems likely utilized small RNA processed from three types of precursors: (1) sense-antisense transcriptional products, (2) genome-encoded, imperfectly complementary hairpin sequences, and (3) larger noncoding RNA precursor sequences. Structural dissection of PIWI proteins along with recent discovery of novel families (including Med13 of the Mediator complex) suggest that emergence of a distinct architecture with the N-terminal domains (also occurring separately fused to endoDNases in prokaryotes) formed via duplication of an ancestral unit was key to their recruitment as primary RNAi effectors and use of small RNAs of certain preferred lengths. Prokaryotic PIWI proteins are typically components of several RNA-directed DNA restriction or CRISPR/Cas systems. However, eukaryotic versions appear to have emerged from a subset that evolved RNA-directed RNAi. They were recruited alongside RNaseIII domains and RNA-dependent RNA polymerase (RdRP) domains, also from prokaryotic systems, to form the core eukaryotic RNAi system. Like certain regulatory systems, RNAi diversified into two distinct but linked arms concomitant with eukaryotic nucleocytoplasmic compartmentalization. Subsequent elaboration of RNAi proceeded via diversification of the core protein machinery through lineage-specific expansions and recruitment of new components from prokaryotes (nucleases and small RNA-modifying enzymes), allowing for diversification of associating small RNAs.
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Affiliation(s)
- Alexander Maxwell Burroughs
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
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36
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Chacko N, Lin X. Non-coding RNAs in the development and pathogenesis of eukaryotic microbes. Appl Microbiol Biotechnol 2013; 97:7989-97. [PMID: 23948725 DOI: 10.1007/s00253-013-5160-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 07/26/2013] [Accepted: 07/29/2013] [Indexed: 12/15/2022]
Abstract
RNA has long been regarded as the important intermediary in the central dogma of gene expression. Recently, the importance of RNAs in the regulation of gene expression became evident with the identification and characterization of non-protein coding transcripts named non-coding RNAs (ncRNAs). The ncRNAs, small and long, are ubiquitously present in all three domains of life and are being recognized for their important roles in genome defense and development. Some of the ncRNAs have been associated with diseases, and therefore, they offer diagnostic and therapeutic potential. In this mini-review, we have highlighted some recent research on the ncRNAs identified in eukaryotic microbes, with special emphasis on fungi that are pathogenic to humans or plants when possible. It is our contention that further elucidation and understanding of ncRNAs will advance our understanding of the development and pathogenesis of eukaryotic microbes and offer alternatives in the diagnosis and treatment of the diseases caused by these pathogens.
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Affiliation(s)
- Nadia Chacko
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843-3258, USA
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37
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Donaldson ME, Saville BJ. Ustilago maydis natural antisense transcript expression alters mRNA stability and pathogenesis. Mol Microbiol 2013; 89:29-51. [PMID: 23650872 PMCID: PMC3739942 DOI: 10.1111/mmi.12254] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2013] [Indexed: 11/29/2022]
Abstract
Ustilago maydis infection of Zea mays leads to the production of thick-walled diploid teliospores that are the dispersal agent for this pathogen. Transcriptome analyses of this model biotrophic basidiomycete fungus identified natural antisense transcripts (NATs) complementary to 247 open reading frames. The U. maydis NAT cDNAs were fully sequenced and annotated. Strand-specific RT-PCR screens confirmed expression and identified NATs preferentially expressed in the teliospore. Targeted screens revealed four U. maydis NATs that are conserved in a related fungus. Expression of NATs in haploid cells, where they are not naturally occurring, resulted in increased steady-state levels of some complementary mRNAs. The expression of one NAT, as-um02151, in haploid cells resulted in a twofold increase in complementary mRNA levels, the formation of sense-antisense double-stranded RNAs, and unchanged Um02151 protein levels. This led to a model for NAT function in the maintenance and expression of stored teliospore mRNAs. In testing this model by deletion of the regulatory region, it was determined that alteration in NAT expression resulted in decreased pathogenesis in both cob and seedling infections. This annotation and functional analysis supports multiple roles for U. maydis NATs in controlling gene expression and influencing pathogenesis.
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Affiliation(s)
- Michael E Donaldson
- Environmental and Life Sciences Graduate ProgramPeterborough, ON, Canada, K9J 7B8
| | - Barry J Saville
- Environmental and Life Sciences Graduate ProgramPeterborough, ON, Canada, K9J 7B8
- Forensic Science Program, Trent UniversityPeterborough, ON, Canada, K9J 7B8
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Panwar V, McCallum B, Bakkeren G. Endogenous silencing of Puccinia triticina pathogenicity genes through in planta-expressed sequences leads to the suppression of rust diseases on wheat. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:521-32. [PMID: 23110316 DOI: 10.1111/tpj.12047] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 10/03/2012] [Accepted: 10/08/2012] [Indexed: 05/20/2023]
Abstract
Rust fungi are destructive plant pathogens. The draft genomes of several wheat-infecting species have been released and potential pathogenicity genes identified through comparative analyses to fungal pathogens that are amenable to genetic manipulation. Functional gene analysis tools are needed to understand the infection process of these obligate parasites and to confirm whether predicted pathogenicity genes could become targets for disease control. We have modified an Agrobacterium tumefaciens-mediated in planta-induced transient gene silencing (PITGS) assay for use in Triticum spp. (wheat), and used this assay to target predicted wheat leaf rust fungus, Puccinia triticina (Pt) pathogenicity genes, a MAP kinase (PtMAPK1), a cyclophilin (PtCYC1) and calcineurin B (PtCNB), to analyze their roles in disease. Agroinfiltration effectively delivered hairpin silencing constructs in wheat, leading to the generation of fungal gene-specific siRNA molecules in infiltrated leaves, and resulting in up to 70% reduction in transcription of the endogenous target genes in superinfected Pt. In vivo silencing caused severe disease suppression, compromising fungal growth and sporulation, as viewed by confocal microscopy and measured by reductions in fungal biomass and emergence of uredinia. Interestingly, using the same gene constructs, suppression of infection by Puccinia graminis and Puccinia striiformis was also achieved. Our results show that A. tumefaciens-mediated PITGS can be used as a reverse-genetics tool to discover gene function in rust fungi. This proof-of-concept study indicates that the targeted fungal transcripts might be important in pathogenesis, and could potentially be used as promising targets for developing RNA interference-based resistance against rust fungi.
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Affiliation(s)
- Vinay Panwar
- Pacific Agri-Food Research Center, Agriculture and Agri-Food Canada, Summerland, BC V0H 1Z0, Canada
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Nunes CC, Dean RA. Host-induced gene silencing: a tool for understanding fungal host interaction and for developing novel disease control strategies. MOLECULAR PLANT PATHOLOGY 2012; 13:519-29. [PMID: 22111693 PMCID: PMC6638818 DOI: 10.1111/j.1364-3703.2011.00766.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Recent discoveries regarding small RNAs and the mechanisms of gene silencing are providing new opportunities to explore fungal pathogen-host interactions and potential strategies for novel disease control. Plant pathogenic fungi are a constant and major threat to global food security; they represent the largest group of disease-causing agents on crop plants on the planet. An initial understanding of RNA silencing mechanisms and small RNAs was derived from model fungi. Now, new knowledge with practical implications for RNA silencing is beginning to emerge from the study of plant-fungus interactions. Recent studies have shown that the expression of silencing constructs in plants designed on fungal genes can specifically silence their targets in invading pathogenic fungi, such as Fusarium verticillioides, Blumeria graminis and Puccinia striiformis f.sp. tritici. Here, we highlight the important general aspects of RNA silencing mechanisms and emphasize recent findings from plant pathogenic fungi. Strategies to employ RNA silencing to investigate the basis of fungal pathogenesis are discussed. Finally, we address important aspects for the development of fungal-derived resistance through the expression of silencing constructs in host plants as a powerful strategy to control fungal disease.
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Affiliation(s)
- Cristiano C Nunes
- Department of Plant Pathology, Fungal Genomics Laboratory, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC 27606, USA
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Nunes CC, Sailsbery JK, Dean RA. Characterization and application of small RNAs and RNA silencing mechanisms in fungi. FUNGAL BIOL REV 2011. [DOI: 10.1016/j.fbr.2011.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Drinnenberg IA, Fink GR, Bartel DP. Compatibility with killer explains the rise of RNAi-deficient fungi. Science 2011; 333:1592. [PMID: 21921191 DOI: 10.1126/science.1209575] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The RNA interference (RNAi) pathway is found in most eukaryotic lineages but curiously is absent in others, including that of Saccharomyces cerevisiae. We show that reconstituting RNAi in S. cerevisiae causes loss of a beneficial double-stranded RNA virus known as killer virus. Incompatibility between RNAi and killer viruses extends to other fungal species in that RNAi is absent in all species known to possess double-stranded RNA killer viruses, whereas killer viruses are absent in closely related species that retained RNAi. Thus, the advantage imparted by acquiring and retaining killer viruses explains the persistence of RNAi-deficient species during fungal evolution.
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Affiliation(s)
- Ines A Drinnenberg
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
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Doyle CE, Donaldson ME, Morrison EN, Saville BJ. Ustilago maydis transcript features identified through full-length cDNA analysis. Mol Genet Genomics 2011; 286:143-59. [PMID: 21750919 DOI: 10.1007/s00438-011-0634-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 06/28/2011] [Indexed: 12/13/2022]
Abstract
Ustilago maydis is the model for investigating basidiomycete biotrophic plant pathogens. To further the annotation of its genome, 12,943 full-length cDNA sequences were used to construct databases for the promoter and untranslated regions of U. maydis genes. A subset of clones was sequenced to determine full cDNA sequences. These and the original ESTs were assembled into contigs representing 3,058, or 45%, of the predicted U. maydis genes. The new sequencing allowed the confirmation of 2,842 gene models, 690 of which contain an intron. The use of full-length cDNA clone sequences ensured that untranslated regions were physically linked to the open reading frames (ORFs), not merely aligned upstream of the start of transcription. Identified sequence features include: (1) over 500 potential short upstream ORFs, (2) 95 gene models that require further annotation, (3) one new potential ORF, (4) varying GC content in different gene regions, (5) a WebLogo motif for the start of translation, (6) the correlation of UTR length with transcript representation in cDNA libraries and with gene function categories, (7) a relationship between natural antisense transcripts and UTR length that differs from that of Saccharomyces cerevisiae, (8) a potential relationship between DNA replication and the control of transcription, and (9) new insights regarding mechanisms for the control of transcription and mRNA maturation in U. maydis.
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Affiliation(s)
- Colleen E Doyle
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON K9J 7B8, Canada
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Ianiri G, Wright SAI, Castoria R, Idnurm A. Development of resources for the analysis of gene function in Pucciniomycotina red yeasts. Fungal Genet Biol 2011; 48:685-95. [PMID: 21402165 DOI: 10.1016/j.fgb.2011.03.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 02/05/2011] [Accepted: 03/08/2011] [Indexed: 11/16/2022]
Abstract
The Pucciniomycotina is an important subphylum of basidiomycete fungi but with limited tools to analyze gene functions. Transformation protocols were established for a Sporobolomyces species (strain IAM 13481), the first Pucciniomycotina species with a completed draft genome sequence, to enable assessment of gene function through phenotypic characterization of mutant strains. Transformation markers were the URA3 and URA5 genes that enable selection and counter-selection based on uracil auxotrophy and resistance to 5-fluoroorotic acid. The wild type copies of these genes were cloned into plasmids that were used for transformation of Sporobolomyces sp. by both biolistic and Agrobacterium-mediated approaches. These resources have been deposited to be available from the Fungal Genetics Stock Center. To show that these techniques could be used to elucidate gene functions, the LEU1 gene was targeted for specific homologous replacement, and also demonstrating that this gene is required for the biosynthesis of leucine in basidiomycete fungi. T-DNA insertional mutants were isolated and further characterized, revealing insertions in genes that encode the homologs of Chs7, Erg3, Kre6, Kex1, Pik1, Sad1, Ssu1 and Tlg1. Phenotypic analysis of these mutants reveals both conserved and divergent functions compared with other fungi. Some of these strains exhibit reduced resistance to detergents, the antifungal agent fluconazole or sodium sulfite, or lower recovery from heat stress. While there are current experimental limitations for Sporobolomyces sp. such as the lack of Mendelian genetics for conventional mating, these findings demonstrate the facile nature of at least one Pucciniomycotina species for genetic manipulation and the potential to develop these organisms into new models for understanding gene function and evolution in the fungi.
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Affiliation(s)
- Giuseppe Ianiri
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, MO 64110, USA
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Abstract
The fungal kingdom is vast, spanning ~1.5 to as many as 5 million species diverse as unicellular yeasts, filamentous fungi, mushrooms, lichens, and both plant and animal pathogens. The fungi are closely aligned with animals in one of the six to eight supergroups of eukaryotes, the opisthokonts. The animal and fungal kingdoms last shared a common ancestor ~1 billion years ago, more recently than other groups of eukaryotes. As a consequence of their close evolutionary history and shared cellular machinery with metazoans, fungi are exceptional models for mammalian biology, but prove more difficult to treat in infected animals. The last common ancestor to the fungal/metazoan lineages is thought to have been unicellular, aquatic, and motile with a posterior flagellum, and certain extant species closely resemble this hypothesized ancestor. Species within the fungal kingdom were traditionally assigned to four phyla, including the basal fungi (Chytridiomycota, Zygomycota) and the more recently derived monophyletic lineage, the dikarya (Ascomycota, Basidiomycota). The fungal tree of life project has revealed that the basal lineages are polyphyletic, and thus there are as many as eight to ten fungal phyla. Fungi that infect vertebrates are found in all of the major lineages, and virulence arose multiple times independently. A sobering recent development involves the species Batrachochytrium dendrobatidis from the basal fungal phylum, the Chytridiomycota, which has emerged to cause global amphibian declines and extinctions. Genomics is revolutionizing our view of the fungal kingdom, and genome sequences for zygomycete pathogens (Rhizopus, Mucor), skin-associated fungi (dermatophytes, Malassezia), and the Candida pathogenic species clade promise to provide insights into the origins of virulence. Here we survey the diversity of fungal pathogens and illustrate key principles revealed by genomics involving sexual reproduction and sex determination, loss of conserved pathways in derived fungal lineages that are retained in basal fungi, and shared and divergent virulence strategies of successful human pathogens, including dimorphic and trimorphic transitions in form. The overarching conclusion is that fungal pathogens of animals have arisen repeatedly and independently throughout the fungal tree of life, and while they share general properties, there are also unique features to the virulence strategies of each successful microbial pathogen.
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Affiliation(s)
- Joseph Heitman
- Department of Molecular Genetics and Microbiology Duke University Medical Center
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Cervantes-Chávez JA, Ali S, Bakkeren G. Response to environmental stresses, cell-wall integrity, and virulence are orchestrated through the calcineurin pathway in Ustilago hordei. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:219-232. [PMID: 20977307 DOI: 10.1094/mpmi-09-10-0202] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In eukaryotes, several biological processes are regulated through calcium signaling. Calcineurin is a calcium-calmodulin-regulated serine/threonine phosphatase consisting of catalytic subunit A and regulatory subunit B. Phosphatase activity resides in the catalytic subunit, which activates by dephosphorylation downstream components such as transcription factor Crz1. The importance of this pathway to respond to environmental stress has been explored in several fungal pathogens. The basidiomycete Ustilago hordei causes covered smut of barley. We addressed the role of the Ca(2+)-calcineurin activated pathway by deleting UhCna1 and UhCnb1. These genes were not essential in U. hordei but the corresponding mutants displayed a variety of phenotypes when applying environmental stress such as sensitivity to pH, temperature, H₂O₂, mono- and divalent cations; and to genotoxic, acid, or oxidative stresses. Cell-wall integrity was compromised and mutants displayed altered cell morphologies. Mating was delayed but not abolished, and combined sensitivities likely explained a severely reduced virulence toward barley plants. Expression analyses revealed that response to salt stress involved the induction of membrane ATPase genes UhEna1 and UhEna2, which were regulated through the calcineurin pathway. Upregulation of UhFKS1, a 1,3-β-d-glucan synthase gene, correlated with the increased amount of 1,3-β-d-glucan in the calcineurin mutants grown under salt stress.
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Wang X, Hsueh YP, Li W, Floyd A, Skalsky R, Heitman J. Sex-induced silencing defends the genome of Cryptococcus neoformans via RNAi. Genes Dev 2010; 24:2566-82. [PMID: 21078820 DOI: 10.1101/gad.1970910] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cosuppression is a silencing phenomenon triggered by the introduction of homologous DNA sequences into the genomes of organisms as diverse as plants, fungi, flies, and nematodes. Here we report sex-induced silencing (SIS), which is triggered by tandem integration of a transgene array in the human fungal pathogen Cryptococcus neoformans. A SXI2a-URA5 transgene array was found to be post-transcriptionally silenced during sexual reproduction. More than half of the progeny that inherited the SXI2a-URA5 transgene became uracil-auxotrophic due to silencing of the URA5 gene. In vegetative mitotic growth, silencing of this transgene array occurred at an ∼250-fold lower frequency, indicating that silencing is induced during the sexual cycle. Central components of the RNAi pathway-including genes encoding Argonaute, Dicer, and an RNA-dependent RNA polymerase-are all required for both meiotic and mitotic transgene silencing. URA5-derived ∼22-nucleotide (nt) small RNAs accumulated in the silenced isolates, suggesting that SIS is mediated by RNAi via sequence-specific small RNAs. Through deep sequencing of the small RNA population in C. neoformans, we also identified abundant small RNAs mapping to repetitive transposable elements, and these small RNAs were absent in rdp1 mutant strains. Furthermore, a group of retrotransposons was highly expressed during mating of rdp1 mutant strains, and an increased transposition/mutation rate was detected in their progeny, indicating that the RNAi pathway squelches transposon activity during the sexual cycle. Interestingly, Ago1, Dcr1, Dcr2, and Rdp1 are translationally induced in mating cells, and Ago1, Dcr1, and Dcr2 localize to processing bodies (P bodies), whereas Rdp1 appears to be nuclear, providing mechanistic insights into the elevated silencing efficiency during sexual reproduction. We hypothesize that the SIS RNAi pathway operates to defend the genome during sexual development.
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Affiliation(s)
- Xuying Wang
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
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Abstract
RNA interference (RNAi), a gene-silencing pathway triggered by double-stranded RNA, is conserved in diverse eukaryotic species but has been lost in the model budding yeast Saccharomyces cerevisiae. Here, we show that RNAi is present in other budding yeast species, including Saccharomyces castellii and Candida albicans. These species use noncanonical Dicer proteins to generate small interfering RNAs, which mostly correspond to transposable elements and Y' subtelomeric repeats. In S. castellii, RNAi mutants are viable but have excess Y' messenger RNA levels. In S. cerevisiae, introducing Dicer and Argonaute of S. castellii restores RNAi, and the reconstituted pathway silences endogenous retrotransposons. These results identify a previously unknown class of Dicer proteins, bring the tool of RNAi to the study of budding yeasts, and bring the tools of budding yeast to the study of RNAi.
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MESH Headings
- Fungal Proteins/genetics
- Fungal Proteins/metabolism
- Gene Expression Profiling
- Genes, Fungal
- Genetic Loci
- Mutation
- Open Reading Frames
- RNA Interference
- RNA, Double-Stranded/genetics
- RNA, Double-Stranded/metabolism
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Repetitive Sequences, Nucleic Acid
- Retroelements
- Ribonuclease III/genetics
- Ribonuclease III/metabolism
- Saccharomyces/genetics
- Saccharomyces/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae Proteins/genetics
- Saccharomyces cerevisiae Proteins/metabolism
- Saccharomycetales/genetics
- Saccharomycetales/metabolism
- Sequence Analysis, RNA
- Transcription, Genetic
- Transformation, Genetic
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Affiliation(s)
- Ines A. Drinnenberg
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - David E. Weinberg
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kathleen T. Xie
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jeffrey P. Mower
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Kenneth H. Wolfe
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Gerald R. Fink
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - David P. Bartel
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Kemppainen MJ, Pardo AG. pHg/pSILBAγ vector system for efficient gene silencing in homobasidiomycetes: optimization of ihpRNA - triggering in the mycorrhizal fungus Laccaria bicolor. Microb Biotechnol 2009; 3:178-200. [PMID: 21255319 PMCID: PMC3836584 DOI: 10.1111/j.1751-7915.2009.00122.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
pSILBAγ silencing vector was constructed for efficient RNA silencing triggering in the model mycorrhizal fungus Laccaria bicolor. This cloning vector carries the Agaricus bisporus gpdII promoter, two multiple cloning sites separated by a L. bicolor nitrate reductase intron and the Aspergillus nidulans trpC terminator. pSILBAγ allows an easy oriented two‐step PCR cloning of hairpin sequences to be expressed in basidiomycetes. With one further cloning step into pHg, a pCAMBIA1300‐based binary vector carrying a hygromycin resistance cassette, the pHg/pSILBAγ plasmid is used for Agrobacterium‐mediated transformation. The pHg/pSILBAγ system results in predominantly single integrations of RNA silencing triggering T‐DNAs in the fungal genome and the integration sites of the transgenes can be resolved by plasmid rescue. pSILBAγ construct and two other pSILBA plasmid variants (pSILBA and pSILBAα) were evaluated for their capacity to silence Laccaria nitrate reductase gene. While all pSILBA variants tested resulted in up to 65–76% of transformants with reduced growth on nitrate, pSILBAγ produced the highest number (65%) of strongly affected fungal strains. The strongly silenced phenotype was shown to correlate with T‐DNA integration in transcriptionally active genomic sites. pHg/pSILBAγ was shown to produce T‐DNAs with minimum CpG methylation in transgene promoter regions which assures the maximum silencing trigger production in Laccaria. Methylation of the target endogene was only slight in RNA silencing triggered with constructs carrying an intronic spacer hairpin sequence. The silencing capacity of the pHg/pSILBAγ was further tested with Laccaria inositol‐1,4,5‐triphosphate 5‐phosphatase gene. Besides its use in silencing triggering, the herein described plasmid system can also be used for transgene expression in Laccaria. pHg/pSILBAγ silencing system is optimized for L. bicolor but it should be highly useful also for other homobasidiomycetes, group of fungi currently lacking molecular tools for RNA silencing.
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Affiliation(s)
- Minna J Kemppainen
- Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Roque Sáenz Peña 352, (B1876BXD) Bernal, Provincia de Buenos Aires, Argentina
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Nakayashiki H, Nguyen QB. RNA interference: roles in fungal biology. Curr Opin Microbiol 2008; 11:494-502. [PMID: 18955156 DOI: 10.1016/j.mib.2008.10.001] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2008] [Revised: 09/26/2008] [Accepted: 10/01/2008] [Indexed: 12/30/2022]
Abstract
The discovery of RNA interference (RNAi) has been the major recent breakthrough in biology. Only a few years after its discovery, RNAi has rapidly become a powerful reverse genetic tool, especially in organisms where gene targeting is inefficient and/or time-consuming. In filamentous fungi, RNAi is not currently used as widely as is gene targeting by homologous recombination that works with practical efficiencies in most model fungal species. However, to explore gene function in filamentous fungi, RNAi has the potential to offer new, efficient tools that gene disruption methods cannot provide. In this review, possible advantages and disadvantages of RNAi for fungal biology in the postgenomics era will be discussed. In addition, we will briefly review recent discoveries on RNAi-related biological phenomena (RNA silencing) in fungi.
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Affiliation(s)
- Hitoshi Nakayashiki
- Laboratory of Plant Pathology, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan.
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