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Córdoba L, Ruiz-Padilla A, Pardo-Medina J, Rodríguez-Romero JL, Ayllón MA. Construction of a Mycoviral Infectious Clone for Reverse Genetics in Botrytis cinerea. Methods Mol Biol 2024; 2751:47-68. [PMID: 38265709 DOI: 10.1007/978-1-0716-3617-6_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
The most important advances in our understanding of the viral life cycle, such as genome replication, packaging, transmission, and host interactions, have been made via the development of viral infectious full-length clones. Here, we describe the detailed protocols for the construction of an infectious clone derived from Botrytis virus F (BVF), a mycoflexivirus infecting the plant pathogenic fungus Botrytis cinerea, the determination of the complete sequence of the cloned mycovirus, the preparation of fungal protoplasts, and the transfection of protoplasts using transcripts derived from the BVF infectious clone.
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Affiliation(s)
- Laura Córdoba
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Madrid, Spain
| | - Ana Ruiz-Padilla
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Madrid, Spain
| | - Javier Pardo-Medina
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Madrid, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Julio L Rodríguez-Romero
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Madrid, Spain
| | - María A Ayllón
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Madrid, Spain.
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Madrid, Spain.
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Khan HA, Baig DI, Bhatti MF. An Overview of Mycoviral Curing Strategies Used in Evaluating Fungal Host Fitness. Mol Biotechnol 2023; 65:1547-1564. [PMID: 36841858 PMCID: PMC9963364 DOI: 10.1007/s12033-023-00695-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/11/2023] [Indexed: 02/27/2023]
Abstract
The number of novel mycoviruses is increasing at a high pace due to advancements in sequencing technologies. As a result, an uncountable number of mycoviral sequences are available in public sequence repositories. However, only genomic information is not sufficient to understand the impact of mycoviruses on their host biology. Biological characterization is required to determine the nature of mycoviruses (cryptic, hypervirulent, or hypovirulent) and to search for mycoviruses with biocontrol and therapeutic potential. Currently, no particular selective method is used as the gold standard against these mycoviral infections. Given the importance of curing, we present an overview of procedures used in preparation of isogenic lines, along with their benefits and drawbacks. We concluded that a combination of single-spore isolation and hyphal tipping is the best fit for preparation of isogenic lines. Furthermore, recent bioinformatic approaches should be introduced in the field of mycovirology to predict virus-specific antivirals to get robust results.
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Affiliation(s)
- Haris Ahmed Khan
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, 44000 Pakistan
- Department of Biotechnology, University of Mianwali, Punjab, 42200 Pakistan
| | - Danish Ilyas Baig
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, 44000 Pakistan
| | - Muhammad Faraz Bhatti
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, 44000 Pakistan
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Popović M, Nuskern L, Peranić K, Vuković R, Katanić Z, Krstin L, Ćurković-Perica M, Leigh DM, Poljak I, Idžojtić M, Rigling D, Ježić M. Physiological variations in hypovirus-infected wild and model long-term laboratory strains of Cryphonectria parasitica. Front Microbiol 2023; 14:1192996. [PMID: 37426020 PMCID: PMC10324583 DOI: 10.3389/fmicb.2023.1192996] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/25/2023] [Indexed: 07/11/2023] Open
Abstract
Introduction Forest ecosystems are highly threatened by the simultaneous effects of climate change and invasive pathogens. Chestnut blight, caused by the invasive phytopathogenic fungus Cryphonectria parasitica, has caused severe damage to European chestnut groves and catastrophic dieback of American chestnut in North America. Within Europe, the impacts of the fungus are widely mitigated through biological control that utilizes the RNA mycovirus: Cryphonectria hypovirus 1 (CHV1). Viral infections, similarly to abiotic factors, can cause oxidative stress in their hosts leading to physiological attrition through stimulating ROS (reactive oxygen species) and NOx production. Methods To fully understand the interactions leading to the biocontrol of chestnut blight, it is vital to determine oxidative stress damage arising during CHV1 infection, especially considering that other abiotic factors, like long-term cultivation of model fungal strains, can also impact oxidative stress. Our study compared CHV1-infected C. parasitica isolates from two Croatian wild populations with CHV1-infected model strains (EP713, Euro7 and CR23) that have experienced long-term laboratory cultivation. Results and Discussion We determined the level of oxidative stress in the samples by measuring stress enzymes' activity and oxidative stress biomarkers. Furthermore, for the wild populations, we studied the activity of fungal laccases, expression of the laccase gene lac1, and a possible effect of CHV1 intra-host diversity on the observed biochemical responses. Relative to the wild isolates, the long-term model strains had lower enzymatic activities of superoxide dismutase (SOD) and glutathione S-transferase (GST), and higher content of malondialdehyde (MDA) and total non-protein thiols. This indicated generally higher oxidative stress, likely arising from their decades-long history of subculturing and freeze-thaw cycles. When comparing the two wild populations, differences between them in stress resilience and levels of oxidative stress were also observed, as evident from the different MDA content. The intra-host genetic diversity of the CHV1 had no discernible effect on the stress levels of the virus-infected fungal cultures. Our research indicated that an important determinant modulating both lac1 expression and laccase enzyme activity is intrinsic to the fungus itself, possibly related to the vc type of the fungus, i.e., vegetative incompatibility genotype.
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Affiliation(s)
- Maja Popović
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Lucija Nuskern
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Karla Peranić
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Rosemary Vuković
- Department of Biology, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Zorana Katanić
- Department of Biology, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Ljiljana Krstin
- Department of Biology, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | | | | | - Igor Poljak
- Faculty of Forestry and Wood Technology, University of Zagreb, Zagreb, Croatia
| | - Marilena Idžojtić
- Faculty of Forestry and Wood Technology, University of Zagreb, Zagreb, Croatia
| | - Daniel Rigling
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Marin Ježić
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
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Ayllón MA, Vainio EJ. Mycoviruses as a part of the global virome: Diversity, evolutionary links and lifestyle. Adv Virus Res 2023; 115:1-86. [PMID: 37173063 DOI: 10.1016/bs.aivir.2023.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Knowledge of mycovirus diversity, evolution, horizontal gene transfer and shared ancestry with viruses infecting distantly related hosts, such as plants and arthropods, has increased vastly during the last few years due to advances in the high throughput sequencing methodologies. This also has enabled the discovery of novel mycoviruses with previously unknown genome types, mainly new positive and negative single-stranded RNA mycoviruses ((+) ssRNA and (-) ssRNA) and single-stranded DNA mycoviruses (ssDNA), and has increased our knowledge of double-stranded RNA mycoviruses (dsRNA), which in the past were thought to be the most common viruses infecting fungi. Fungi and oomycetes (Stramenopila) share similar lifestyles and also have similar viromes. Hypothesis about the origin and cross-kingdom transmission events of viruses have been raised and are supported by phylogenetic analysis and by the discovery of natural exchange of viruses between different hosts during virus-fungus coinfection in planta. In this review we make a compilation of the current information on the genome organization, diversity and taxonomy of mycoviruses, discussing their possible origins. Our focus is in recent findings suggesting the expansion of the host range of many viral taxa previously considered to be exclusively fungal, but we also address factors affecting virus transmissibility and coexistence in single fungal or oomycete isolates, as well as the development of synthetic mycoviruses and their use in investigating mycovirus replication cycles and pathogenicity.
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Affiliation(s)
- María A Ayllón
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación Agraria y Alimentaria (INIA/CSIC), Campus de Montegancedo, Pozuelo de Alarcón, Madrid, Spain; Departamento Biotecnología-Biología Vegetal, E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Madrid, Spain.
| | - Eeva J Vainio
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Helsinki, Finland
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5
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Guo J, Zhou X, Xie F, Cao J, Liu S, Zhong J, Zhu H. Hypovirulence caused by mycovirus in Colletotrichum fructicola. FRONTIERS IN PLANT SCIENCE 2022; 13:1038781. [PMID: 36275531 PMCID: PMC9585321 DOI: 10.3389/fpls.2022.1038781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
Colletotrichum fructicola is a pathogenic fungus causing leaf black spot and fruit rot disease in a wide variety of crops. Some mycoviruses that cause detrimental effects on fungal hosts could be useful in studying the pathogenesis of fungal hosts. In this study, we reported two mycoviruses, Colletotrichum fructicola ourmia-like virus 1- Colletotrichum gloeosporioides ourmia-like virus 1 (CfOLV1-CgOLV1) and Colletotrichum fructicola ourmia-like virus 2 (CfOLV2), from a C. fructicola fungus. The complete genome sequences of CfOLV1-CgOLV1 and CfOLV2 contain 2,516 bp and 2,048 bp, respectively. Both of these viruses contain only one open reading frame (ORF), which encodes an RNA-dependent RNA polymerase (RdRp). CfOLV1-CgOLV1 was identical as the previously reported virus CgOLV1. Phylogenetic analysis showed that CfOLV2 is closely related to Scleroulivirus and Magoulivirus in the family Botourmiaviridae. Virus elimination and horizontal transmission experiments proved that the associated mycoviruses could reduce the pathogenicity of the host C. fructicola. In addition, we found that the virus-containing strains showed a much higher percentage of appressorium formation and more melanin production compared to isogenic virus-free strain, and the presence of the virus is detrimental to the growth of host fungi and regulates the integrity of the cell wall. Transcriptomic analysis showed that mycovirus infection caused various abnormal genes expression in C. fructicola. To the best of our knowledge, this is the first report of a hypovirulence-associated ourmia-like mycovirus in C. fructicola.
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Affiliation(s)
| | | | | | | | | | - Jie Zhong
- *Correspondence: Hongjian Zhu, ;Jie Zhong,
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Bocos-Asenjo IT, Niño-Sánchez J, Ginésy M, Diez JJ. New Insights on the Integrated Management of Plant Diseases by RNA Strategies: Mycoviruses and RNA Interference. Int J Mol Sci 2022; 23:9236. [PMID: 36012499 PMCID: PMC9409477 DOI: 10.3390/ijms23169236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 08/09/2022] [Accepted: 08/15/2022] [Indexed: 11/25/2022] Open
Abstract
RNA-based strategies for plant disease management offer an attractive alternative to agrochemicals that negatively impact human and ecosystem health and lead to pathogen resistance. There has been recent interest in using mycoviruses for fungal disease control after it was discovered that some cause hypovirulence in fungal pathogens, which refers to a decline in the ability of a pathogen to cause disease. Cryphonectria parasitica, the causal agent of chestnut blight, has set an ideal model of management through the release of hypovirulent strains. However, mycovirus-based management of plant diseases is still restricted by limited approaches to search for viruses causing hypovirulence and the lack of protocols allowing effective and systemic virus infection in pathogens. RNA interference (RNAi), the eukaryotic cell system that recognizes RNA sequences and specifically degrades them, represents a promising. RNA-based disease management method. The natural occurrence of cross-kingdom RNAi provides a basis for host-induced gene silencing, while the ability of most pathogens to uptake exogenous small RNAs enables the use of spray-induced gene silencing techniques. This review describes the mechanisms behind and the potential of two RNA-based strategies, mycoviruses and RNAi, for plant disease management. Successful applications are discussed, as well as the research gaps and limitations that remain to be addressed.
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Affiliation(s)
- Irene Teresa Bocos-Asenjo
- Department of Plant Production and Forest Resources, University of Valladolid, 34004 Palencia, Spain
- iuFOR-Sustainable Forest Management Research Institute, University of Valladolid-INIA, 34004 Palencia, Spain
| | - Jonatan Niño-Sánchez
- Department of Plant Production and Forest Resources, University of Valladolid, 34004 Palencia, Spain
- iuFOR-Sustainable Forest Management Research Institute, University of Valladolid-INIA, 34004 Palencia, Spain
| | - Mireille Ginésy
- Department of Plant Production and Forest Resources, University of Valladolid, 34004 Palencia, Spain
- iuFOR-Sustainable Forest Management Research Institute, University of Valladolid-INIA, 34004 Palencia, Spain
| | - Julio Javier Diez
- Department of Plant Production and Forest Resources, University of Valladolid, 34004 Palencia, Spain
- iuFOR-Sustainable Forest Management Research Institute, University of Valladolid-INIA, 34004 Palencia, Spain
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7
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Wang X, Lai J, Hu H, Yang J, Zang K, Zhao F, Zeng G, Liao Q, Gu Z, Du Z. Infection of Nigrospora nonsegmented RNA Virus 1 Has Important Biological Impacts on a Fungal Host. Viruses 2022; 14:v14040795. [PMID: 35458525 PMCID: PMC9029208 DOI: 10.3390/v14040795] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/04/2022] [Accepted: 04/06/2022] [Indexed: 01/27/2023] Open
Abstract
Nigrospora nonsegmented RNA virus 1 (NoNRV1) has been reported previously in the fungus Nigrospora oryzae, but its biological effects on its host are unknown. In this work, we isolated a strain 9-1 of N. oryzae from a chrysanthemum leaf and identified NoNRV1 infection in the isolated strain. The genome sequence of NoNRV1 identified here is highly homologous to that of the isolate HN-21 of NoNRV1 previously reported; thus, we tentatively designated the newly identified NoNRV1 as NoNRV1-ZJ. Drug treatment with Ribavirin successfully removed NoNRV1-ZJ from the strain 9-1, which provided us with an ideal control to determine the biological impacts of NoNRV1 infection on host fungi. By comparing the virus-carrying (9-1) and virus-cured (9-1C) strains, our results indicated that infection with NoNRV1 promoted the pigmentation of the host cells, while it had no discernable effects on host growth on potato dextrose agar plates when subjected to osmotic or oxidative stress. Interestingly, we observed inhibitory impacts of virus infection on the thermotolerance of N. oryzae and the pathogenicity of the host fungus in cotton leaves. Collectively, our work provides clear evidence of the biological relevance of NoNRV1 infection in N. oryzae, including pigmentation, hypovirulence, and thermotolerance.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Zhouhang Gu
- Correspondence: (Z.G.); (Z.D.); Tel.: +86-571-8684-3195 (Z.D.)
| | - Zhiyou Du
- Correspondence: (Z.G.); (Z.D.); Tel.: +86-571-8684-3195 (Z.D.)
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8
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Li R, Zhao L, Li S, Chen F, Qiu J, Bai L, Chen B. The Autophagy-Related Gene CpAtg4 Is Required for Fungal Phenotypic Traits, Stress Tolerance, and Virulence in Cryphonectria parasitica. PHYTOPATHOLOGY 2022; 112:299-307. [PMID: 34033505 DOI: 10.1094/phyto-01-21-0015-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Autophagy is an evolutionarily ancient process wherein cells are able to break down intracellular contents to support normal physiology and development. Autophagosome formation is regulated by several different proteins, including the key cysteine protease Atg4. The contribution of Atg4 protein in the pathogenic fungus Cryphonectria parasitica, which causes blight in chestnut plants, has not been completely understood. In this context, we aimed to investigate the role of Atg4 during autophagy formation and their contribution to nonautophagic events in C. parasitica. By complementation assay, we determined that the CpAtg4 gene from C. parasitica was able to functionally complement the deletion of yeast Atg4. Using a yeast two-hybrid assay system, we confirmed that CpAtg4 and CpAtg8 directly interact with one another, and amino acids 377 to 409 of CpAtg4 were identified as being responsible for its binding with CpAtg8. The deletion mutant of CpAtg4 did not demonstrate positive monodansylcadaverine staining, which indicated that CpAtg4 is required for autophagy in C. parasitica. Moreover, the ΔCpAtg4 strain exhibited a decrease in aerial hyphae formation and sporulation, and reduction in virulence on apple and chestnut stem. The ΔCpAtg4 strains were also more sensitive to H2O2 and Congo red-induced stress. We further determined that amino acids 377 to 409 of CpAtg4 were essential for the function of CpAtg4 in vivo. Together, our findings indicated that CpAtg4 is required for the autophagy formation, fungal phenotypic traits, stress tolerance, and virulence in C. parasitica.
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Affiliation(s)
- Ru Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Lijiu Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Shuangcai Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Fengyue Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Jinfeng Qiu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Lingyun Bai
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Baoshan Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
- College of Agriculture, Guangxi University, Nanning 530004, People's Republic of China
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9
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Omnipresence of Partitiviruses in Rice Aggregate Sheath Spot Symptom-Associated Fungal Isolates from Paddies in Thailand. Viruses 2021; 13:v13112269. [PMID: 34835075 PMCID: PMC8625198 DOI: 10.3390/v13112269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 01/09/2023] Open
Abstract
Partitiviruses are one of the most prevalent double-stranded RNA viruses that have been identified mostly in filamentous fungi and plants. Partitiviruses generally infect host fungi asymptomatically but infrequently exert significant effect(s) on morphology and virulence, thus being considered a potential source of biological control agents against pathogenic fungi. In this study, we performed a screening for mycoviruses of a collection of Thai isolates of rice fungal pathogen Rhizoctonia oryzae-sativae, a causal agent of rice aggregated sheath spot disease. As a result, 36% of tested isolates carried potentially viral double-stranded RNAs with sizes ranging from 2 to 3 kbp. By conventional cDNA library construction and RNA-seq, we determined six new alphapartitiviruses that infected three isolates: tentatively named Rhizoctonia oryzae-sativae partitivirus 1 to 6 (RosPV1-6). Furthermore, RT-PCR detection of each virus revealed their omnipresent nature in different R. oryzae-sativae isolates. Although virus-curing of basidiomycetous fungi is generally difficult, our repeated attempts successfully obtained virus-free (for RosPV1, RosPV2, and uncharacterized partitiviruses), isogenic strain of R. oryzae-sativae TSS190442. The virus-cured strain showed slightly faster colony growth on the synthetic media and severe symptom development on the rice sheath compared to its virus-infected counterpart. Overall, this study shed light on the distribution of partitiviruses in R. oryzae-sativae in a paddy environment and exemplified a virus-curing protocol that may be applicable for other basidiomycetous fungi.
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10
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Casas LL, Azevedo JL, Almeida LN, Costa-Neto PQ, Bianco RA, Pereira JO. Mycoviruses infecting Colletotrichum spp.: A comprehensive review. BRAZ J BIOL 2021; 83:e248975. [PMID: 34550289 DOI: 10.1590/1519-6984.248975] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 05/07/2021] [Indexed: 06/01/2024] Open
Abstract
Colletotrichum is one of the most economically important fungal genera, which affects a wide range of hosts, specifically tropical and subtropical crops. Thus far, there have been several records of mycovirus infection in Colletotrichum spp., primarily by viruses of the Partitiviridae family. There have also been records of infections by mycoviruses of the Chrysoviridae family. Mycoviruses are (+)ssRNA and dsRNA genome viruses, which may or may not be enveloped. To date, no mycovirus with a DNA genome has been isolated from Colletotrichum spp. Typically, mycoviruses cause latent infections, although hypo- and hypervirulence have also been reported in Colletotrichum spp. In addition to its effects on pathogenic behavior, mycovirus infection can lead to important physiological changes, such as altered morphological characteristics, reduced vegetative growth, and suppressed conidia production. Therefore, research on mycoviruses infecting phytopathogenic fungi can help develop alternative methods to chemical control, which can cause irreversible damage to humans and the environment. From an agricultural perspective, mycoviruses can contribute to sustainable agriculture as biological control agents via changes in fungal physiology, ultimately resulting in the total loss of or reduction in the virulence of these pathogens.
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Affiliation(s)
- L L Casas
- Universidade do Estado do Amazonas - UEA, Programa de Pós-graduação em Biodiversidade e Biotecnologia - Bionorte, Manaus, AM, Brasil
| | - J L Azevedo
- Universidade de São Paulo - USP, Escola Superior de Agricultura Luiz de Queiroz, Piracicaba, SP, Brasil
| | - L N Almeida
- Universidade Federal do Amazonas - UFAM, Faculdade de Ciências Agrárias, Manaus, AM, Brasil
| | - P Q Costa-Neto
- Universidade Federal do Amazonas - UFAM, Faculdade de Ciências Agrárias, Manaus, AM, Brasil
| | - R A Bianco
- Centro Universitário do Norte - Uninorte, Manaus, AM, Brasil
| | - J O Pereira
- Universidade Federal do Amazonas - UFAM, Faculdade de Ciências Agrárias, Manaus, AM, Brasil
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11
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A Novel Mycovirus Evokes Transcriptional Rewiring in the Fungus Malassezia and Stimulates Beta Interferon Production in Macrophages. mBio 2020; 11:mBio.01534-20. [PMID: 32873760 PMCID: PMC7468202 DOI: 10.1128/mbio.01534-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Malassezia species represent the most common fungal inhabitant of the mammalian skin microbiome and are natural skin commensal flora. However, these fungi are also associated with a variety of clinical skin disorders. Recent studies have reported associations of Malassezia with Crohn’s disease and pancreatic cancer, further implicating this fungal genus in inflammatory and neoplastic disease states. Because M. sympodialis has lost genes involved in RNA interference (RNAi), we hypothesized Malassezia could harbor dsRNA mycoviruses. Indeed, we identified a novel mycovirus of the totivirus family in several Malassezia species and characterized the MsMV1 mycovirus of M. sympodialis. We found conditions that lead to curing of the virus and analyzed isogenic virus-infected/virus-cured strains to determine MsMV1 genetic and pathogenic impacts. MsMV1 induces a strong overexpression of transcription factors and ribosomal genes, while downregulating cellular metabolism. Moreover, MsMV1 induced a significantly higher level of beta interferon expression in cultured macrophages. This study sheds light on the mechanisms of pathogenicity of Malassezia, focusing on a previously unidentified novel mycovirus. Mycoviruses infect fungi, and while most persist asymptomatically, there are examples of mycoviruses having both beneficial and detrimental effects on their host. Virus-infected Saccharomyces and Ustilago strains exhibit a killer phenotype conferring a growth advantage over uninfected strains and other competing yeast species, whereas hypovirus-infected Cryphonectria parasitica displays defects in growth, sporulation, and virulence. In this study, we identify a double-stranded RNA (dsRNA) mycovirus in five Malassezia species. Sequence analysis reveals it to be a totivirus with two dsRNA segments: a larger 4.5-kb segment with genes encoding components for viral replication and maintenance, and a smaller 1.4-kb segment encoding a novel protein. Furthermore, transcriptome sequencing (RNA-seq) of virus-infected versus virus-cured Malassezia sympodialis revealed an upregulation of dozens of ribosomal components in the cell, suggesting the virus modifies the transcriptional and translational landscapes of the cell. Given that Malassezia is the most abundant fungus on human skin, we assessed the impact of the mycovirus in a murine epicutaneous infection model. Although infection with virus-infected strains was not associated with an increased inflammatory response, we did observe enhanced skin colonization in one of two virus-infected M. sympodialis strains. Noteworthy, beta interferon expression was significantly upregulated in bone marrow-derived macrophages when challenged with virus-infected, compared to virus-cured, M. sympodialis, suggesting that the presence of the virus can induce an immunological response. Although many recent studies have illuminated how widespread mycoviruses are, there are relatively few in-depth studies about their impact on disease caused by the host fungus. We describe here a novel mycovirus in Malassezia and its possible implications in pathogenicity.
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Kolp M, Double ML, Fulbright DW, MacDonald WL, Jarosz AM. Spatial and temporal dynamics of the fungal community of chestnut blight cankers on American chestnut (Castanea dentata) in Michigan and Wisconsin. FUNGAL ECOL 2020. [DOI: 10.1016/j.funeco.2020.100925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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13
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Li P, Bhattacharjee P, Wang S, Zhang L, Ahmed I, Guo L. Mycoviruses in Fusarium Species: An Update. Front Cell Infect Microbiol 2019; 9:257. [PMID: 31380300 PMCID: PMC6657619 DOI: 10.3389/fcimb.2019.00257] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/03/2019] [Indexed: 12/12/2022] Open
Abstract
Fusarium is an important genus of plant pathogenic fungi, and is widely distributed in soil and associated with plants worldwide. The diversity of mycoviruses in Fusarium is increasing continuously due to the development and extensive use of state-of-the-art RNA deep sequencing techniques. To date, fully-sequenced mycoviruses have been reported in 13 Fusarium species: Fusarium asiaticum, F. boothii, F. circinatum, F. coeruleum, F. globosum, F. graminearum, F. incarnatum, F. langsethiae, F. oxysporum, F. poae, F. pseudograminearum, F. solani, and F. virguliforme. Most Fusarium mycoviruses establish latent infections, but some mycoviruses such as Fusarium graminearum virus 1 (FgV1), Fusarium graminearum virus-ch9 (FgV-ch9), Fusarium graminearum hypovirus 2 (FgHV2), and Fusarium oxysporum f. sp. dianthi mycovirus 1 (FodV1) cause hypovirulence. Rapid advances in various omics technologies used to elucidate genes or biological processes can facilitate an improved understanding of mycovirus-host interactions. The review aims to illuminate the recent advances in studies of mycoviruses in Fusarium, including those related to diversity, molecular mechanisms of virus-host interaction. We also discuss the induction and suppression of RNA silencing including the role of RNAi components as an antiviral defense response.
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Affiliation(s)
- Pengfei Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Pallab Bhattacharjee
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shuangchao Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lihang Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Irfan Ahmed
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lihua Guo
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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14
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Xiong Q, Zhang L, Waletich J, Zhang L, Zhang C, Zheng X, Qian Y, Zhang Z, Wang Y, Cheng Q. Characterization of the Papain-Like Protease p29 of the Hypovirus CHV1-CN280 in Its Natural Host Fungus Cryphonectria parasitica and Nonhost Fungus Magnaporthe oryzae. PHYTOPATHOLOGY 2019; 109:736-747. [PMID: 30592694 DOI: 10.1094/phyto-08-18-0318-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Cryphonectria hypovirus 1 strain CN280 (CHV1-CN280) was isolated from North China and exhibited typical hypovirulence-associated traits. We previously reported that CHV1-CN280 was more aggressive and had a higher horizontal transmission ability between Cryphonectria parasitica isolates belonging to different vegetative compatibility groups than two other CHV1 hypoviruses (namely, CHV1-EP713 and CHV1-Euro7), thus displaying greater potential for biological control of chestnut blight. The genome sequence of CHV1-CN280 shared approximately 70% identity with three other hypoviruses (CHV1-EP713, CHV1-Euro7, and CHV1-EP721). The coding region for p29, a papain-like protease encoded by CHV1-CN280 hypovirus, displayed an average of only approximately 60% amino acid identity among them, while the identity between the other three CHV1 isolates was higher than 89%. Protease p29 acted as a virus-encoded determinant responsible for altering fungal host phenotypes in other CHV1 isolates. In this study, the impacts of CHV1-CN280 p29 expression in virus-free C. parasitica were investigated. CHV1-CN280 p29 expression in C. parasitica resulted in significantly reduced sporulation, pigmentation, extracellular laccase activities, and pathogenicity, which is consistent with previous investigations. Subsequently, the potential of CHV1-CN280 p29 as a viral determinant responsible for suppression of host phenotypes in other phytopathogenic fungi such as Magnaporthe oryzae, the causal agent of rice blast disease, was discussed. However, heterologous expression of p29 in M. oryzae induced the opposite effect on sporulation, extracellular laccase activities, and pathogenicity; had no significant effect on pigmentation and mycelial growth; and contributed to extracellular peroxidase activities, suggesting that CHV1-CN280 p29 may disturb a unique regulatory pathway in C. parasitica, rather than a basic regulatory pathway conserved in diverse range of fungi. Alternatively, CHV1-CN280 p29-mediated modulation of fungal phenotypes may be facilitated by the specific interaction between p29 and a special fungal-host component, which exists only with C. parasitica but not M. oryzae.
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Affiliation(s)
- Qin Xiong
- 1 Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
- 2 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Linqiao Zhang
- 2 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- 3 Institute of Agricultural Sciences for Lixiahe Region in Jiangsu, Yangzhou 225009, China
| | - Justin Waletich
- 4 Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, U.S.A.; and
| | - Linlin Zhang
- 1 Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Chen Zhang
- 1 Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Xinyue Zheng
- 1 Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Yulin Qian
- 1 Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Zhengguang Zhang
- 2 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuanchao Wang
- 2 Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Qiang Cheng
- 5 The Southern Modern Forestry Collaborative Innovation Center, Nanjing Forestry University, Nanjing 210037, China
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15
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Meyer JB, Chalmandrier L, Fässler F, Schefer C, Rigling D, Prospero S. Role of Fresh Dead Wood in the Epidemiology and the Biological Control of the Chestnut Blight Fungus. PLANT DISEASE 2019; 103:430-438. [PMID: 30632896 DOI: 10.1094/pdis-05-18-0796-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The invasive fungus Cryphonectria parasitica, the causal agent of chestnut blight, is able to survive and sporulate on the bark of fresh dead Castanea sativa wood for at least 2 years. Here, we experimentally investigated the role of fresh dead wood in the epidemiology of chestnut blight, specifically in the spread of the hyperparasitic virus Cryphonectria hypovirus 1, which acts as biocontrol agent of C. parasitica. A total of 152 artificially initiated, virulent bark cankers in four chestnut stands were treated with virus-infected asexual spores originating either from sporulating dead wood or from a spore suspension. Molecular markers for both the virus and the fungal carrier were used to examine the spread of the applied biocontrol virus. Fourteen months after treatment, 42 to 76% of the conidial spray-treated cankers and 50 to 60% of the cankers exposed to a sporulating dead stem had been virus infected by the applied hypovirulent conidia in all four study sites. Virus infection reduced canker expansion and promoted canker healing (callusing). Thus, fresh chestnut dead wood may play an important role in supporting the successful spread of natural hypovirulence in chestnut forests. Further, combined with the application of virus-infected conidial suspensions, it may help promote the establishment of artificially released hypoviruses in chestnut stands to control chestnut blight.
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Affiliation(s)
- Joana Beatrice Meyer
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), CH-8903 Birmensdorf, Switzerland
| | - Loïc Chalmandrier
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), CH-8903 Birmensdorf, Switzerland; Landscape Ecology, Institute of Terrestrial Ecosystems, ETH Zürich, Switzerland; and Department of Botany, University of Wyoming, Laramie, WY 82071-2000, U.S.A
| | - Fabio Fässler
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), CH-8903 Birmensdorf, Switzerland
| | - Christopher Schefer
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), CH-8903 Birmensdorf, Switzerland
| | - Daniel Rigling
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), CH-8903 Birmensdorf, Switzerland
| | - Simone Prospero
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), CH-8903 Birmensdorf, Switzerland
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16
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Rigling D, Borst N, Cornejo C, Supatashvili A, Prospero S. Genetic and Phenotypic Characterization of Cryphonectria hypovirus 1 from Eurasian Georgia. Viruses 2018; 10:v10120687. [PMID: 30513977 PMCID: PMC6315935 DOI: 10.3390/v10120687] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/30/2018] [Accepted: 11/30/2018] [Indexed: 01/18/2023] Open
Abstract
Cryphonectria hypovirus 1 (CHV-1) infects the chestnut blight fungus Cryphonectria parasitica and acts as a biological control agent against this harmful tree disease. In this study, we screened the recently characterized C. parasitica population in Eurasian Georgia for the presence of CHV-1. We found 62 CHV-1 infected C. parasitica isolates (9.3%) among a total of 664 isolates sampled in 14 locations across Georgia. The prevalence of CHV-1 at the different locations ranged from 0% in the eastern part of the country to 29% in the western part. Sequencing of two specific regions of the viral genome one each in ORFA and ORFB revealed a unique CHV-1 subtype in Georgia. This subtype has a recombinant pattern combining the ORFA region from the subtype F2 and the ORFB region from subtype D. All 62 viral strains belonged to this Georgian CHV-1 subtype (subtype G). The CHV-1 subtype G strongly reduced the parasitic growth of C. parasitica isolates from Georgia, with a more severe effect on the European genepool compared to the Georgian genepool. The CHV-1 subtype detected in Georgia provides a valuable candidate for biological control applications in the Caucasus region.
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Affiliation(s)
- Daniel Rigling
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf; Switzerland.
| | - Nora Borst
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf; Switzerland.
| | - Carolina Cornejo
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf; Switzerland.
| | - Archil Supatashvili
- Vasil Gulisashvili Forestry Institute, Agricultural University of Georgia, 0186 Tbilisi, Georgia.
| | - Simone Prospero
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf; Switzerland.
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17
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Wang J, Guo M, Sun Y, Bian Y, Zhou Y, Xu Z. Genetic variation and phylogenetic analyses reveal transmission clues of Lentinula edodes partitivirus 1 (LePV1) from the Chinese L. edodes core collection. Virus Res 2018; 255:127-132. [DOI: 10.1016/j.virusres.2018.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/14/2018] [Accepted: 07/19/2018] [Indexed: 11/28/2022]
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18
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Abstract
Viruses are an important but sequence-diverse and often understudied component of the phytobiome. We succinctly review current information on how plant viruses directly affect plant health and physiology and consequently have the capacity to modulate plant interactions with their biotic and abiotic environments. Virus interactions with other biota in the phytobiome, including arthropods, fungi, and nematodes, may also impact plant health. For example, viruses interact with and modulate the interface between plants and insects. This has been extensively studied for insect-vectored plant viruses, some of which also infect their vectors. Other viruses have been shown to alter the impacts of plant-interacting phytopathogenic and nonpathogenic fungi and bacteria. Viruses that infect nematodes have also recently been discovered, but the impact of these and phage infecting soil bacteria on plant health remain largely unexplored.
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Affiliation(s)
- James E Schoelz
- Division of Plant Sciences, University of Missouri, Columbia, Missouri 65211, USA
| | - Lucy R Stewart
- Corn, Soybean and Wheat Quality Research Unit, United States Department of Agriculture Agricultural Research Service (USDA-ARS), Wooster, Ohio 44691, USA;
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19
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Double ML, Jarosz AM, Fulbright DW, Davelos Baines A, MacDonald WL. Evaluation of Two Decades of Cryphonectria parasitica Hypovirus Introduction in an American Chestnut Stand in Wisconsin. PHYTOPATHOLOGY 2018; 108:702-710. [PMID: 29318913 DOI: 10.1094/phyto-10-17-0354-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Hypovirus-infected Cryphonectria parasitica strains were introduced in a large stand of American chestnut (>4,000 individuals) in western Wisconsin (USA) to evaluate whether hypoviruses can serve as biological control agents. They were deployed by treating cankers from 1992 to 1997 and again from 2004 to 2014. After 17 years of hypovirus introductions within an area of the stand with the longest history of disease, isolation of hypovirus-infected strains increased from 55% in 1994 to 86% in 2014 from cankers that were treated. During the same period, isolation from cankers that arose on trees with treated cankers increased from 29 to 72% and from 15 to 84% for cankers on nearby trees that received no treatment. Tree survivorship over the 23-year study period for trees with treated cankers was 51% compared with 31% for trees that were not treated. Introduction of hypovirus has resulted in the regrowth of the crowns of many large-diameter trees. Putative recovery of American chestnut in this stand provides evidence that prolonged hypovirus treatment can act as a biological control when limited numbers of vegetative compatibility types of C. parasitica exist.
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Affiliation(s)
- Mark L Double
- First and fifth authors: Division of Plant and Soil Sciences, West Virginia University, Morgantown 26506; second author: Departments of Plant Biology, and Plant, Soils and Microbial Sciences, and The Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing 48824; third author: Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing 48824; and fourth author: Department of Biology, University of Wisconsin-La Crosse, La Crosse 54601
| | - Andrew M Jarosz
- First and fifth authors: Division of Plant and Soil Sciences, West Virginia University, Morgantown 26506; second author: Departments of Plant Biology, and Plant, Soils and Microbial Sciences, and The Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing 48824; third author: Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing 48824; and fourth author: Department of Biology, University of Wisconsin-La Crosse, La Crosse 54601
| | - Dennis W Fulbright
- First and fifth authors: Division of Plant and Soil Sciences, West Virginia University, Morgantown 26506; second author: Departments of Plant Biology, and Plant, Soils and Microbial Sciences, and The Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing 48824; third author: Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing 48824; and fourth author: Department of Biology, University of Wisconsin-La Crosse, La Crosse 54601
| | - Anita Davelos Baines
- First and fifth authors: Division of Plant and Soil Sciences, West Virginia University, Morgantown 26506; second author: Departments of Plant Biology, and Plant, Soils and Microbial Sciences, and The Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing 48824; third author: Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing 48824; and fourth author: Department of Biology, University of Wisconsin-La Crosse, La Crosse 54601
| | - William L MacDonald
- First and fifth authors: Division of Plant and Soil Sciences, West Virginia University, Morgantown 26506; second author: Departments of Plant Biology, and Plant, Soils and Microbial Sciences, and The Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing 48824; third author: Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing 48824; and fourth author: Department of Biology, University of Wisconsin-La Crosse, La Crosse 54601
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20
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Nuskern L, Ježić M, Liber Z, Mlinarec J, Ćurković-Perica M. Cryphonectria hypovirus 1-Induced Epigenetic Changes in Infected Phytopathogenic Fungus Cryphonectria parasitica. MICROBIAL ECOLOGY 2018; 75:790-798. [PMID: 28865007 DOI: 10.1007/s00248-017-1064-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/24/2017] [Indexed: 06/07/2023]
Abstract
Biotic stress caused by virus infections induces epigenetic changes in infected plants and animals, but this is the first report on methylation pattern changes in a fungus after mycovirus infection. As a model pathosystem for mycovirus-host interactions, we used Cryphonectria hypovirus 1 (CHV1) and its host fungus Cryphonectria parasitica, in which deregulation of methylation cycle enzymes upon virus infection was observed previously. Six CHV1 strains of different subtypes were transferred into three different C. parasitica isolates in order to assess the effect of different CHV1 strains and/or subtypes on global cytosine methylation level in infected fungus, using methylation-sensitive amplification polymorphism (MSAP). Infection with CHV1 affected the methylation pattern of the C. parasitica genome; it increased the number and diversity of methylated, hemi-methylated, and total MSAP markers found in infected fungal isolates compared to virus-free controls. The increase in methylation levels correlated well with the CHV1-induced reduction of fungal growth in vitro, indicating that C. parasitica genome methylation upon CHV1 infection, rather than being the defensive mechanism of the fungus, is more likely to be the virulence determinant of the virus. Furthermore, the severity of CHV1 effect on methylation levels of infected C. parasitica isolates depended mostly on individual CHV1 strains and on the combination of host and virus genomes, rather than on the virus subtype. These novel findings broaden our knowledge about CHV1 strains which could potentially be used in human-aided biocontrol of chestnut blight, a disease caused by C. parasitica in chestnut forest ecosystems and orchards.
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Affiliation(s)
- Lucija Nuskern
- Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR-10 000, Zagreb, Croatia
| | - Marin Ježić
- Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR-10 000, Zagreb, Croatia
| | - Zlatko Liber
- Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR-10 000, Zagreb, Croatia
| | - Jelena Mlinarec
- Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR-10 000, Zagreb, Croatia
| | - Mirna Ćurković-Perica
- Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR-10 000, Zagreb, Croatia.
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Mlinarec J, Nuskern L, Ježić M, Rigling D, Ćurković-Perica M. Molecular evolution and invasion pattern of Cryphonectria hypovirus 1 in Europe: Mutation rate, and selection pressure differ between genome domains. Virology 2018; 514:156-164. [PMID: 29179038 DOI: 10.1016/j.virol.2017.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 01/08/2023]
Abstract
Understanding virus evolution is a fundamental goal of virology, evolutionary biology, and disease epidemiology. We provide a detailed analysis of evolution and origin of Cryphonectria hypovirus 1 (CHV1) populations in Europe, based on the complete genome sequence of all European subtypes. Phylogenetic analyses divided European strains into two closely related clades. Strains of the subtype I belong to the first, while strains of the subtypes F1, D and E belong to the second clade suggesting that the subtypes F1, D and E are more closely related than previously thought. Strains of the subtype F2 appeared to be recombinant; subtypes F1/D/E contributed a larger fraction of sequence while subtype I contributed a smaller fraction. The p29 was the most variable domain, while the replication-associated large ORF B protein was the most conserved domain within the CHV1. Low sequence similarity, predominant negative selection and frequent recombination characterise the evolution of CHV1.
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Affiliation(s)
- Jelena Mlinarec
- Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR-10 000 Zagreb, Croatia
| | - Lucija Nuskern
- Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR-10 000 Zagreb, Croatia
| | - Marin Ježić
- Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR-10 000 Zagreb, Croatia
| | - Daniel Rigling
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland
| | - Mirna Ćurković-Perica
- Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR-10 000 Zagreb, Croatia.
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Rigling D, Prospero S. Cryphonectria parasitica, the causal agent of chestnut blight: invasion history, population biology and disease control. MOLECULAR PLANT PATHOLOGY 2018; 19:7-20. [PMID: 28142223 PMCID: PMC6638123 DOI: 10.1111/mpp.12542] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 12/19/2016] [Accepted: 01/26/2017] [Indexed: 05/25/2023]
Abstract
Chestnut blight, caused by Cryphonectria parasitica, is a devastating disease infecting American and European chestnut trees. The pathogen is native to East Asia and was spread to other continents via infected chestnut plants. This review summarizes the current state of research on this pathogen with a special emphasis on its interaction with a hyperparasitic mycovirus that acts as a biological control agent of chestnut blight. TAXONOMY Cryphonectria parasitica (Murr.) Barr. is a Sordariomycete (ascomycete) fungus in the family Cryphonectriaceae (Order Diaporthales). Closely related species that can also be found on chestnut include Cryphonectria radicalis, Cryphonectria naterciae and Cryphonectria japonica. HOST RANGE Major hosts are species in the genus Castanea (Family Fagaceae), particularly the American chestnut (C. dentata), the European chestnut (C. sativa), the Chinese chestnut (C. mollissima) and the Japanese chestnut (C. crenata). Minor incidental hosts include oaks (Quercus spp.), maples (Acer spp.), European hornbeam (Carpinus betulus) and American chinkapin (Castanea pumila). DISEASE SYMPTOMS Cryphonectria parasitica causes perennial necrotic lesions (so-called cankers) on the bark of stems and branches of susceptible host trees, eventually leading to wilting of the plant part distal to the infection. Chestnut blight cankers are characterized by the presence of mycelial fans and fruiting bodies of the pathogen. Below the canker the tree may react by producing epicormic shoots. Non-lethal, superficial or callusing cankers on susceptible host trees are usually associated with mycovirus-induced hypovirulence. DISEASE CONTROL After the introduction of C. parasitica into a new area, eradication efforts by cutting and burning the infected plants/trees have mostly failed. In Europe, the mycovirus Cryphonectria hypovirus 1 (CHV-1) acts as a successful biological control agent of chestnut blight by causing so-called hypovirulence. CHV-1 infects C. parasitica and reduces its parasitic growth and sporulation capacity. Individual cankers can be therapeutically treated with hypovirus-infected C. parasitica strains. The hypovirus may subsequently spread to untreated cankers and become established in the C. parasitica population. Hypovirulence is present in many chestnut-growing regions of Europe, either resulting naturally or after biological control treatments. In North America, disease management of chestnut blight is mainly focused on breeding with the goal to backcross the Chinese chestnut's blight resistance into the American chestnut genome.
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Affiliation(s)
- Daniel Rigling
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)Birmensdorf8903Switzerland
| | - Simone Prospero
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)Birmensdorf8903Switzerland
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23
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Nuskern L, Tkalec M, Ježić M, Katanić Z, Krstin L, Ćurković-Perica M. Cryphonectria hypovirus 1-Induced Changes of Stress Enzyme Activity in Transfected Phytopathogenic Fungus Cryphonectria parasitica. MICROBIAL ECOLOGY 2017; 74:302-311. [PMID: 28160056 DOI: 10.1007/s00248-017-0945-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 01/22/2017] [Indexed: 06/06/2023]
Abstract
Cryphonectria parasitica is a phytopathogenic fungus introduced from Eastern Asia to North America and to Europe, where it causes chestnut blight, a devastating disease of chestnut trees. The disease can be biologically controlled utilising the mycovirus Cryphonectria hypovirus 1 (CHV1), which changes the physiology of the host, reducing its virulence towards chestnut. We measured fungal growth in vitro and activities of glutathione S-transferase, catalase and superoxide dismutase, enzymes involved in oxidative stress response, to elucidate the effects of CHV1 infection on the host. Six CHV1 strains of different subtypes and three fungal isolates were used in different combinations to better represent natural conditions, where higher genetic diversity of both fungus and virus is expected. The infection with different CHV1 strains decreased in vitro growth rate of infected fungal isolates and increased activity of their stress enzymes in most of the studied fungus/virus combinations, indicating increased oxidative stress following CHV1 infection. All our field CHV1 strains belong to the Italian subtype, but while strain M56-1 had equal or even stronger effect on its fungal host than prototypic strain EP713 of French subtype F1, strain B11 had no effect. Thus, the severity of the observed effects depended on a particular virus strain, fungal isolate, and the combination of the two, rather than solely on the virus subtype. Since previous research showed discordance between accumulation of mRNA and stress-related proteins in CHV1 infected C. parasitica, our results emphasise the importance of enzymes' activity measurements as an invaluable extension of transcriptomic and proteomic analyses.
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Affiliation(s)
- Lucija Nuskern
- Department of Biology, Faculty of Science, University of Zagreb, Marulicev trg 9a, 10000, Zagreb, Croatia
| | - Mirta Tkalec
- Department of Biology, Faculty of Science, University of Zagreb, Marulicev trg 9a, 10000, Zagreb, Croatia
| | - Marin Ježić
- Department of Biology, Faculty of Science, University of Zagreb, Marulicev trg 9a, 10000, Zagreb, Croatia
| | - Zorana Katanić
- Department of Biology, University of Josip Juraj Strossmayer in Osijek, Ulica cara Hadrijana 8A, 31000, Osijek, Croatia
| | - Ljiljana Krstin
- Department of Biology, University of Josip Juraj Strossmayer in Osijek, Ulica cara Hadrijana 8A, 31000, Osijek, Croatia
| | - Mirna Ćurković-Perica
- Department of Biology, Faculty of Science, University of Zagreb, Marulicev trg 9a, 10000, Zagreb, Croatia.
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Brusini J, Wayne ML, Franc A, Robin C. The impact of parasitism on resource allocation in a fungal host: the case of Cryphonectria parasitica and its mycovirus, Cryphonectria Hypovirus 1. Ecol Evol 2017; 7:5967-5976. [PMID: 28808558 PMCID: PMC5551080 DOI: 10.1002/ece3.3143] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 04/18/2017] [Accepted: 04/25/2017] [Indexed: 12/04/2022] Open
Abstract
Parasites are known to profoundly affect resource allocation in their host. In order to investigate the effects of Cryphonectria Hypovirus 1 (CHV1) on the life-history traits of its fungal host Cryphonectria parasitica, an infection matrix was completed with the cross-infection of six fungal isolates by six different viruses. Mycelial growth, asexual sporulation, and spore size were measured in the 36 combinations, for which horizontal and vertical transmission of the viruses was also assessed. As expected by life-history theory, a significant negative correlation was found between host somatic growth and asexual reproduction in virus-free isolates. Interestingly this trade-off was found to be positive in infected isolates, illustrating the profound changes in host resource allocation induced by CHV1 infection. A significant and positive relationship was also found in infected isolates between vertical transmission and somatic growth. This last relationship suggests that in this system, high levels of virulence could be detrimental to the vertical transmission of the parasite. Those results underscore the interest of studying host-parasite interaction within the life-history theory framework, which might permit a more accurate understanding of the nature of the modifications triggered by parasite infection on host biology.
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Affiliation(s)
- Jérémie Brusini
- Harbor Branch Oceanographic InstituteFlorida Atlantic UniversityFort PierceFLUSA
- BIOGECOINRAUniversity of BordeauxCestasFrance
- Department of BiologyUniversity of FloridaGainesvilleFLUSA
| | - Marta L. Wayne
- Department of BiologyUniversity of FloridaGainesvilleFLUSA
| | - Alain Franc
- BIOGECOINRAUniversity of BordeauxCestasFrance
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Du Y, Lin Y, Zhou X, Wang K, Fang S, Deng Q. Full-length sequence and genome analysis of CHV1-CN280, a North China isolate of cryphonectria hypovirus 1. Arch Virol 2017; 162:1811-1818. [PMID: 28247097 DOI: 10.1007/s00705-017-3296-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/13/2017] [Indexed: 11/29/2022]
Abstract
CHV1-CN280 is a North China isolate of cryphonectria hypovirus 1 (CHV1), which has high horizontal transmission ability. The complete genomic sequence of CHV1-CN280 was determined and analyzed. Compared with other reported CHV1s, the genome of CHV1-CN280 shows some significantly different characteristics. The junction of the two open reading frames (ORFs) of CHV1-CN280 is AUGUAUAA, while in other reported CHV1s, it is UAAUG. The genomic sequence of CHV1-CN280 shows a high level of similarity to other reported CHV1s in the 3' portion, but in some sections of the 5' portion (the region around the start codon of ORFA, the region around the predicted cleavage site of p29 and p40, and the 5'-portion of p48 coding region), the nucleotide sequence identity is lower than 50%. The p29 of CHV1-CN280 shares only about 60% identity with other sequenced CHV1 isolates at the amino acid level. Full-length genomic recombination analysis suggests that several recombination events have occurred in the ORFB coding region between CHV1-CN280 and two subtype I CHV1 isolates (CHV1-Euro7 or CHV1-EP721). RT-PCR primers were designed according to the genomic sequence of CHV1-CN280 to study the genetic diversity of CHV1 in East Asia. Phylogenetic analysis showed that the East Asian CHV1s were quite different from the five assigned subtypes in Europe, and seven new CHV1 subtypes were identified in this study.
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Affiliation(s)
- Yanan Du
- Hubei Collaborative Innovation Center for Grain Industry, Engineering Research Center of Ecology and Agricultural Use of Wetland, College of Agriculture, Yangtze University, Ministry of Education, Jingzhou, 434025, Hubei, China
| | - Yuan Lin
- Hubei Collaborative Innovation Center for Grain Industry, Engineering Research Center of Ecology and Agricultural Use of Wetland, College of Agriculture, Yangtze University, Ministry of Education, Jingzhou, 434025, Hubei, China
| | - Xuan Zhou
- Hubei Collaborative Innovation Center for Grain Industry, Engineering Research Center of Ecology and Agricultural Use of Wetland, College of Agriculture, Yangtze University, Ministry of Education, Jingzhou, 434025, Hubei, China
| | - Kerong Wang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Shouguo Fang
- Hubei Collaborative Innovation Center for Grain Industry, Engineering Research Center of Ecology and Agricultural Use of Wetland, College of Agriculture, Yangtze University, Ministry of Education, Jingzhou, 434025, Hubei, China
| | - Qingchao Deng
- Hubei Collaborative Innovation Center for Grain Industry, Engineering Research Center of Ecology and Agricultural Use of Wetland, College of Agriculture, Yangtze University, Ministry of Education, Jingzhou, 434025, Hubei, China.
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26
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Krstin L, Katanić Z, Ježić M, Poljak I, Nuskern L, Matković I, Idžojtić M, Ćurković-Perica M. Biological control of chestnut blight in Croatia: an interaction between host sweet chestnut, its pathogen Cryphonectria parasitica and the biocontrol agent Cryphonectria hypovirus 1. PEST MANAGEMENT SCIENCE 2017; 73:582-589. [PMID: 27288259 DOI: 10.1002/ps.4335] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Chestnut blight, caused by the fungus Cryphonectria parasitica, is a severe chestnut disease that can be controlled with naturally occurring hypoviruses in many areas of Europe. The aim of this research was to measure the effect of different Cryphonectria hypovirus 1 (CHV1) strains on the growth of the fungal host and select strains that could potentially be used for human-mediated biocontrol in forests and orchards, and to investigate whether and how chestnut-fungus-virus interactions affect the development and growth of the lesion area on cut stems. RESULTS Two Croatian CHV1 strains (CR23 and M56/1) were selected as potential biocontrol agents. The sequencing of CHV1/ORF-A showed that both of these virus strains belonged to the Italian subtype of CHV1. In vitro transfection of selected virus strains from hypovirulent to genetically diverse virus-free fungal isolates and subsequent inoculation of all virus/fungus combinations on stems of genetically diverse sweet chestnut trees revealed that Croatian virus strain CR23 had an equally hypovirulent effect on the host as the strong French strain CHV1-EP713, while M56/1 had a weaker effect. Furthermore, it was shown that in some cases the same hypovirus/fungus combinations induced various degrees of canker development on different chestnut genotypes. CONCLUSION Some CHV1 strains belonging to the Italian subtype have similar hypovirulent effects on C. parasitica to those belonging to the French subtype. Furthermore, chestnut susceptibility and recovery could be influenced by the response of chestnut trees to particular hypovirulent C. parasitica isolates, and virus-fungus-chestnut interactions could have significant implications for the success of chestnut blight biocontrol. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Ljiljana Krstin
- Department of Biology, University of J. J. Strossmayer in Osijek, Osijek, Croatia
| | - Zorana Katanić
- Department of Biology, University of J. J. Strossmayer in Osijek, Osijek, Croatia
| | - Marin Ježić
- Division of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Igor Poljak
- Department of Forest Genetics, Dendrology and Botany, Faculty of Forestry, University of Zagreb, Zagreb, Croatia
| | - Lucija Nuskern
- Division of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Ivana Matković
- Department of Biology, University of J. J. Strossmayer in Osijek, Osijek, Croatia
| | - Marilena Idžojtić
- Department of Forest Genetics, Dendrology and Botany, Faculty of Forestry, University of Zagreb, Zagreb, Croatia
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Charlton ND, Cubeta MA. Transmission of the M2 double-stranded RNA inRhizoctonia solanianastomosis group 3 (AG-3). Mycologia 2017. [DOI: 10.1080/15572536.2007.11832517] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - Marc A. Cubeta
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, 27695-7616
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28
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Kunova A, Pizzatti C, Cerea M, Gazzaniga A, Cortesi P. New formulation and delivery method of Cryphonectria parasitica for biological control of chestnut blight. J Appl Microbiol 2016; 122:180-187. [PMID: 27748552 DOI: 10.1111/jam.13328] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 09/06/2016] [Accepted: 10/13/2016] [Indexed: 11/29/2022]
Abstract
AIMS This study aimed to develop a new formulation of Cryphonectria parasitica hypovirulent mycelium suitable for inoculations of tall trees from the ground. Cryphonectria parasitica hypovirulent strains are widely used for biological control of chestnut blight. However, it is often inconsistent and ineffective not only for biological reasons but also because the current manual application of hypovirulent strains on adult plants is difficult, time-consuming and expensive. Here, we propose an improved formulation and more effective mode of application of hypovirulent strains, which could boost chestnut blight biocontrol. METHODS AND RESULTS The Cp 4.2H hypovirulent strain was formulated as mycelium discs with polyethylene glycol and hydroxypropyl methylcellulose, loaded into lead-free pellets that are used as carriers to inoculate cankers on chestnut stems by shooting. The formulation of mycelium did not hamper its viability which was stable, with an estimated shelf life of 72 days at 6 ± 1°C. The inoculum effectiveness was confirmed ex planta and in planta in a small-scale pilot study in field, where formulated mycelium discs of hypovirulent strain Cp 4.2H were inoculated by airgun shot method into the chestnut bark. In planta, Cp 4.2H was recovered in 37% of bark samples taken around the inoculated points 1 year after the treatment. CONCLUSIONS We demonstrated that the proposed airgun shooting inoculation method of C. parasitica hypovirulent strain formulated as mycelium discs is suitable for treatment of adult chestnut trees. SIGNIFICANCE AND IMPACT OF THE STUDY The proposed method could be a valid alternative to the traditional manual technique of chestnut biocontrol. The main advantages are the cost-effectiveness and the ease to treat high-positioned, otherwise unreachable cankers both in orchards and forests.
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Affiliation(s)
- A Kunova
- Department of Food, Environmental and Nutritional Sciences, University of Milan, Milan, Italy
| | - C Pizzatti
- Department of Food, Environmental and Nutritional Sciences, University of Milan, Milan, Italy
| | - M Cerea
- Department of Pharmaceutical Sciences, University of Milan, Milan, Italy
| | - A Gazzaniga
- Department of Pharmaceutical Sciences, University of Milan, Milan, Italy
| | - P Cortesi
- Department of Food, Environmental and Nutritional Sciences, University of Milan, Milan, Italy
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29
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Rowley PA, Ho B, Bushong S, Johnson A, Sawyer SL. XRN1 Is a Species-Specific Virus Restriction Factor in Yeasts. PLoS Pathog 2016; 12:e1005890. [PMID: 27711183 PMCID: PMC5053509 DOI: 10.1371/journal.ppat.1005890] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/23/2016] [Indexed: 02/07/2023] Open
Abstract
In eukaryotes, the degradation of cellular mRNAs is accomplished by Xrn1 and the cytoplasmic exosome. Because viral RNAs often lack canonical caps or poly-A tails, they can also be vulnerable to degradation by these host exonucleases. Yeast lack sophisticated mechanisms of innate and adaptive immunity, but do use RNA degradation as an antiviral defense mechanism. One model is that the RNA of yeast viruses is subject to degradation simply as a side effect of the intrinsic exonuclease activity of proteins involved in RNA metabolism. Contrary to this model, we find a highly refined, species-specific relationship between Xrn1p and the "L-A" totiviruses of different Saccharomyces yeast species. We show that the gene XRN1 has evolved rapidly under positive natural selection in Saccharomyces yeast, resulting in high levels of Xrn1p protein sequence divergence from one yeast species to the next. We also show that these sequence differences translate to differential interactions with the L-A virus, where Xrn1p from S. cerevisiae is most efficient at controlling the L-A virus that chronically infects S. cerevisiae, and Xrn1p from S. kudriavzevii is most efficient at controlling the L-A-like virus that we have discovered within S. kudriavzevii. All Xrn1p orthologs are equivalent in their interaction with another virus-like parasite, the Ty1 retrotransposon. Thus, the activity of Xrn1p against totiviruses is not simply an incidental consequence of the enzymatic activity of Xrn1p, but rather Xrn1p co-evolves with totiviruses to maintain its potent antiviral activity and limit viral propagation in Saccharomyces yeasts. Consistent with this, we demonstrated that Xrn1p physically interacts with the Gag protein encoded by the L-A virus, suggesting a host-virus interaction that is more complicated than just Xrn1p-mediated nucleolytic digestion of viral RNAs.
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Affiliation(s)
- Paul A. Rowley
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado, United States of America
- Section of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America
| | - Brandon Ho
- Section of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America
| | - Sarah Bushong
- Section of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America
| | - Arlen Johnson
- Section of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America
| | - Sara L. Sawyer
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado, United States of America
- Section of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America
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30
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Marzano SYL, Hobbs HA, Nelson BD, Hartman GL, Eastburn DM, McCoppin NK, Domier LL. Transfection of Sclerotinia sclerotiorum with in vitro transcripts of a naturally occurring interspecific recombinant of Sclerotinia sclerotiorum hypovirus 2 significantly reduces virulence of the fungus. J Virol 2015; 89:5060-71. [PMID: 25694604 PMCID: PMC4403457 DOI: 10.1128/jvi.03199-14] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 02/16/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED A recombinant strain of Sclerotinia sclerotiorum hypovirus 2 (SsHV2) was identified from a North American Sclerotinia sclerotiorum isolate (328) from lettuce (Lactuca sativa L.) by high-throughput sequencing of total RNA. The 5'- and 3'-terminal regions of the genome were determined by rapid amplification of cDNA ends. The assembled nucleotide sequence was up to 92% identical to two recently reported SsHV2 strains but contained a deletion near its 5' terminus of more than 1.2 kb relative to the other SsHV2 strains and an insertion of 524 nucleotides (nt) that was distantly related to Valsa ceratosperma hypovirus 1. This suggests that the new isolate is a heterologous recombinant of SsHV2 with a yet-uncharacterized hypovirus. We named the new strain Sclerotinia sclerotiorum hypovirus 2 Lactuca (SsHV2L) and deposited the sequence in GenBank with accession number KF898354. Sclerotinia sclerotiorum isolate 328 was coinfected with a strain of Sclerotinia sclerotiorum endornavirus 1 and was debilitated compared to cultures of the same isolate that had been cured of virus infection by cycloheximide treatment and hyphal tipping. To determine whether SsHV2L alone could induce hypovirulence in S. sclerotiorum, a full-length cDNA of the 14,538-nt viral genome was cloned. Transcripts corresponding to the viral RNA were synthesized in vitro and transfected into a virus-free isolate of S. sclerotiorum, DK3. Isolate DK3 transfected with SsHV2L was hypovirulent on soybean and lettuce and exhibited delayed maturation of sclerotia relative to virus-free DK3, completing Koch's postulates for the association of hypovirulence with SsHV2L. IMPORTANCE A cosmopolitan fungus, Sclerotinia sclerotiorum infects more than 400 plant species and causes a plant disease known as white mold that produces significant yield losses in major crops annually. Mycoviruses have been used successfully to reduce losses caused by fungal plant pathogens, but definitive relationships between hypovirus infections and hypovirulence in S. sclerotiorum were lacking. By establishing a cause-and-effect relationship between Sclerotinia sclerotiorum hypovirus Lactuca (SsHV2L) infection and the reduction in host virulence, we showed direct evidence that hypoviruses have the potential to reduce the severity of white mold disease. In addition to intraspecific recombination, this study showed that recent interspecific recombination is an important factor shaping viral genomes. The construction of an infectious clone of SsHV2L allows future exploration of the interactions between SsHV2L and S. sclerotiorum, a widespread fungal pathogen of plants.
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Affiliation(s)
| | - Houston A Hobbs
- Department of Crop Sciences, University of Illinois, Urbana, Illinois, USA
| | - Berlin D Nelson
- Department of Plant Pathology, North Dakota State University, Fargo, North Dakota, USA
| | - Glen L Hartman
- Department of Crop Sciences, University of Illinois, Urbana, Illinois, USA United States Department of Agriculture/Agricultural Research Service, Urbana, Illinois, USA
| | - Darin M Eastburn
- Department of Crop Sciences, University of Illinois, Urbana, Illinois, USA
| | - Nancy K McCoppin
- United States Department of Agriculture/Agricultural Research Service, Urbana, Illinois, USA
| | - Leslie L Domier
- Department of Crop Sciences, University of Illinois, Urbana, Illinois, USA United States Department of Agriculture/Agricultural Research Service, Urbana, Illinois, USA
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Ghabrial SA, Castón JR, Jiang D, Nibert ML, Suzuki N. 50-plus years of fungal viruses. Virology 2015; 479-480:356-68. [PMID: 25771805 DOI: 10.1016/j.virol.2015.02.034] [Citation(s) in RCA: 454] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 01/31/2015] [Accepted: 02/19/2015] [Indexed: 10/23/2022]
Abstract
Mycoviruses are widespread in all major taxa of fungi. They are transmitted intracellularly during cell division, sporogenesis, and/or cell-to-cell fusion (hyphal anastomosis), and thus their life cycles generally lack an extracellular phase. Their natural host ranges are limited to individuals within the same or closely related vegetative compatibility groups, although recent advances have established expanded experimental host ranges for some mycoviruses. Most known mycoviruses have dsRNA genomes packaged in isometric particles, but an increasing number of positive- or negative-strand ssRNA and ssDNA viruses have been isolated and characterized. Although many mycoviruses do not have marked effects on their hosts, those that reduce the virulence of their phytopathogenic fungal hosts are of considerable interest for development of novel biocontrol strategies. Mycoviruses that infect endophytic fungi and those that encode killer toxins are also of special interest. Structural analyses of mycoviruses have promoted better understanding of virus assembly, function, and evolution.
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Affiliation(s)
- Said A Ghabrial
- Plant Pathology Department, University of Kentucky, Lexington, KY, USA.
| | - José R Castón
- Department of Structure of Macromolecules, Centro Nacional Biotecnologıa/CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Daohong Jiang
- State Key Lab of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei Province, PR China
| | - Max L Nibert
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, Japan
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32
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Mutagenesis of the catalytic and cleavage site residues of the hypovirus papain-like proteases p29 and p48 reveals alternative processing and contributions to optimal viral RNA accumulation. J Virol 2014; 88:11946-54. [PMID: 25100848 DOI: 10.1128/jvi.01489-14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The positive-stranded RNA genome of the prototypic virulence-attenuating hypovirus CHV-1/EP713 contains two open reading frames (ORF), each encoding an autocatalytic papain-like leader protease. Protease p29, derived from the N-terminal portion of ORF A, functions as a suppressor of RNA silencing, while protease p48, derived from the N-terminal portion of ORF B, is required for viral RNA replication. The catalytic and cleavage site residues required for autoproteolytic processing have been functionally mapped in vitro for both proteases but not confirmed in the infected fungal host. We report here the mutagenesis of the CHV-1/EP713 infectious cDNA clone to define the requirements for p29 and p48 cleavage and the role of autoproteolysis in the context of hypovirus replication. Mutation of the catalytic cysteine and histidine residues for either p29 or p48 was tolerated but reduced viral RNA accumulation to ca. 20 to 50% of the wild-type level. Mutation of the p29 catalytic residues caused an accumulation of unprocessed ORF A product p69. Surprisingly, the release of p48 from the ORF B-encoded polyprotein was not prevented by mutation of the p48 catalytic and cleavage site residues and was independent of p29. The results show that, while dispensable for hypovirus replication, the autocatalytic processing of the leader proteases p29 and p48 contributes to optimal virus RNA accumulation. The role of the predicted catalytic residues in autoproteolytic processing of p29 was confirmed in the infected host, while p48 was found to also undergo alternative processing independent of the encoded papain-like protease activities. Importance: Hypoviruses are positive-strand RNA mycoviruses that attenuate virulence of their pathogenic fungal hosts. The prototypic hypovirus CHV-1/EP713, which infects the chestnut bight fungus Cryphonetria parasitica, encodes two papain-like autocatalytic leader proteases, p29 and p48, that also have important functions in suppressing the RNA silencing antiviral defense response and in viral RNA replication, respectively. The mutational analyses of the CHV-1/EP713 infectious cDNA clone, reported here, define the requirements for p29 and p48 cleavage and the functional importance of autoproteolysis in the context of hypovirus replication and exposed an alternative p48 processing pathway independent of the encoded papain-like protease activities. These findings provide additional insights into hypovirus gene expression, replication, and evolution and inform ongoing efforts to engineer hypoviruses for interrogating and modulating fungal virulence.
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Feau N, Dutech C, Brusini J, Rigling D, Robin C. Multiple introductions and recombination in Cryphonectria hypovirus 1: perspective for a sustainable biological control of chestnut blight. Evol Appl 2014; 7:580-96. [PMID: 24944571 PMCID: PMC4055179 DOI: 10.1111/eva.12157] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 03/03/2014] [Accepted: 03/06/2014] [Indexed: 11/26/2022] Open
Abstract
Cryphonectria hypovirus 1 (CHV1) is a mycovirus which decreases the virulence of its fungal host Cryphonectria parasitica, the causal agent of chestnut blight recently introduced in Europe. The understanding of the evolutionary processes which have shaped CHV1 populations in Europe is required to develop a sustainable biocontrol strategy targeting chestnut blight and effective in European chestnut forests. To retrace the evolutionary history of CHV1, we analyzed sequences from two genomic regions on a collection of 55 CHV1 strains from France and northern Spain, two countries where multiple introductions of C. parasitica occurred. Several recombination events and variable selection pressures contributed to CHV1 evolution, agreeing with a non-clock-like diversification rate. These two mechanisms may be at the origin of CHV1 population diversity observed in western Europe. Considering the actual prevalence of CHV1 and its association with host genotypes, multiple introductions of CHV1 may have occurred in Europe, some of them directly from Asia and some of them through North America. Although some viral strains remained with low frequency in their introduction area, multiple infections might have allowed homologous recombination within parental sequences. Some of these recombinant lineages are associated with the spread of CHV1 in European regions.
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Affiliation(s)
- Nicolas Feau
- INRA, UMR1202 BIOGECO F-33610, Cestas, France ; University Bordeaux, BIOGECO, UMR 1202 F-33400, Talence, France ; TAIGA-Lab, Forest Sciences Centre, University of British Columbia #3618-2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Cyril Dutech
- INRA, UMR1202 BIOGECO F-33610, Cestas, France ; University Bordeaux, BIOGECO, UMR 1202 F-33400, Talence, France
| | - Jérémie Brusini
- INRA, UMR1202 BIOGECO F-33610, Cestas, France ; University Bordeaux, BIOGECO, UMR 1202 F-33400, Talence, France ; Department of Ecology and Evolutionary Biology, Earth and Marine Sciences Building, University of California Santa Cruz, CA, 95064, USA
| | - Daniel Rigling
- WSL Swiss Federal Research Institute CH-8903, Birmensdorf, Switzerland
| | - Cécile Robin
- INRA, UMR1202 BIOGECO F-33610, Cestas, France ; University Bordeaux, BIOGECO, UMR 1202 F-33400, Talence, France
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34
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Simoni S, Nannelli R, Roversi PF, Turchetti T, Bouneb M. Thyreophagus corticalis as a vector of hypovirulence in Cryphonectria parasitica in chestnut stands. EXPERIMENTAL & APPLIED ACAROLOGY 2014; 62:363-375. [PMID: 24114335 DOI: 10.1007/s10493-013-9738-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/26/2013] [Indexed: 06/02/2023]
Abstract
The natural spread of hypovirulence in Cryphonectria parasitica (Murr.) Barr. occurs in chestnut (Castanea sativa Mill) stands and orchards in Italy and other European countries, leading to spontaneous recovery of the diseased trees. Little is known about how hypovirulence spreads in chestnut stands but various corticolous mite species frequently detected on chestnut cankers could be one of the many factors playing a role in the spread. Artificial virulent cankers created in inoculation field tests and treated with Thyreophagus corticalis (Acari, Sarcoptiformes, Acaridae) raised on hypovirulent cultures showed similar growth to those treated with mycelia of the hypovirulent strain over 18 months of inoculation. Cultures re-isolated from virulent cankers treated with mites were found to contain hypovirus like those derived from pairings of virulent and hypovirulent strains. Viral dsRNA could be carried externally and/or ingested by mites from the hypovirulent mycelia and then transmitted to the mycelia of virulent strains, causing their conversion. In a laboratory study, all fecal pellets collected from mites reared on hypovirulent and virulent strains grown on semi-selective media gave rise to colonies of C. parasitica with similar morphological characters and virulence to the original cultures. Field inoculation of stump sprouts with the resulting colonies revealed that mite digestive tract passage did not alter the virulence of the studied strains. These results are of interest for the biological control of chestnut blight.
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Affiliation(s)
- Sauro Simoni
- Agricultural Research Council, Research Centre for Agrobiology and Pedology, Consiglio per la Ricerca e Sperimentazione in Agricoltura, CRA-ABP, via di Lanciola 12/a, 50125, Florence, Italy,
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35
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Suzuki N. [Cryphonectria parasitica as a host of fungal viruses: a tool useful to unravel the mycovirus world]. Uirusu 2014; 64:11-24. [PMID: 25765976 DOI: 10.2222/jsv.64.11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
There appear to be over a million of fungal species including those that have been unidentified and unreported, where a variety of viruses make a world as well. Studies on a very small number of them conducted during the last two decades demonstrated the infectivity of fungal viruses that had previously been assumed to be inheritable, indigenus and non-infectious. Also, great technical advances were achieved. The chest blight fungus (Cryphonectria parasitica), a phytopathogenic ascomycetous fungus, has emerged as a model filamentous fungus for fungal virology. The genome sequence with annotations, albeit not thorough, many useful research tools, and gene manipulation technologies are available for this fungus. Importantly, C. parasitica can support replication of homologous viruses naturally infecting it, in addition to heterologous viruses infecting another plant pathogenic fungus, Rosellinia necatrix taxonomically belonging to a different order. In this article, I overview general properties of fungal viruses and advantages of the chestnut blight fungus as a mycovirus host. Furthermore, I introduce two recent studies carried out using this fungal host:''Defective interfering RNA and RNA silencing that regulate the replication of a partitivirus'' and'' RNA silencing and RNA recombination''.
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Affiliation(s)
- Nobuhiro Suzuki
- Agrivirology Laboratory, Group of Plant/Microbe Interactions, Institute of Plant Science and Resources, Okayama University
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Xie J, Jiang D. New insights into mycoviruses and exploration for the biological control of crop fungal diseases. ANNUAL REVIEW OF PHYTOPATHOLOGY 2014; 52:45-68. [PMID: 25001452 DOI: 10.1146/annurev-phyto-102313-050222] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Mycoviruses are viruses that infect fungi. A growing number of novel mycoviruses have expanded our knowledge of virology, particularly in taxonomy, ecology, and evolution. Recent progress in the study of mycoviruses has comprehensively improved our understanding of the properties of mycoviruses and has strengthened our confidence to explore hypovirulence-associated mycoviruses that control crop diseases. In this review, the advantages of using hypovirulence-associated mycoviruses to control crop diseases are discussed, and, as an example, the potential for Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1) to control the stem rot of rapeseed (Brassica napus) is also introduced. Fungal vegetative incompatibility is likely to be the key factor that limits the wide utilization of mycoviruses to control crop diseases; however, there are suggested strategies for resolving this problem.
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Affiliation(s)
- Jiatao Xie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China;
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Hyder R, Pennanen T, Hamberg L, Vainio EJ, Piri T, Hantula J. Two viruses of Heterobasidion confer beneficial, cryptic or detrimental effects to their hosts in different situations. FUNGAL ECOL 2013. [DOI: 10.1016/j.funeco.2013.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Dawe AL, Nuss DL. Hypovirus molecular biology: from Koch's postulates to host self-recognition genes that restrict virus transmission. Adv Virus Res 2013; 86:109-47. [PMID: 23498905 DOI: 10.1016/b978-0-12-394315-6.00005-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The idea that viruses can be used to control fungal diseases has been a driving force in mycovirus research since the earliest days. Viruses in the family Hypoviridae associated with reduced virulence (hypovirulence) of the chestnut blight fungus, Cryphonectria parasitica, have held a prominent place in this research. This has been due in part to the severity of the chestnut blight epidemics in North America and Europe and early reports of hypovirulence-mediated mitigation of disease in European forests and successful application for control of chestnut blight in chestnut orchards. A more recent contributing factor has been the development of a hypovirus/C. parasitica experimental system that has overcome many of the challenges associated with mycovirus research, stemming primarily from the exclusive intracellular lifestyle shared by all mycoviruses. This chapter will focus on hypovirus molecular biology with an emphasis on the development of the hypovirus/C. parasitica experimental system and its contributions to fundamental and practical advances in mycovirology and the broader understanding of virus-host interactions and fungal pathogenesis.
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Affiliation(s)
- Angus L Dawe
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
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Abstract
Botrytis cinerea (gray mold) is one of the most widespread and destructive fungal diseases of horticultural crops. Propagation and dispersal is usually by asexual conidia but the sexual stage (Botryotinia fuckeliana (de Bary) Whetzel) also occurs in nature. DsRNAs, indicative of virus infection, are common in B. cinerea, but only four viruses (Botrytis virus F (BVF), Botrytis virus X (BVX), Botrytis cinerea mitovirus 1 (BcMV1), and Botrytis porri RNA virus) have been sequenced. BVF and BVX are unusual mycoviruses being ssRNA flexous rods and have been designated the type species of the genera Mycoflexivirus and Botrexvirus (family Betaflexivirdae), respectively. The reported effects of viruses on Botrytis range from negligible to severe, with Botrytis cinerea mitovirus 1 causing hypovirulence. Little is currently known about the effects of viruses on Botrytis metabolism but recent complete sequencing of the B. cinerea genome now provides an opportunity to investigate the host-pathogen interactions at the molecular level. There is interest in the possible use of mycoviruses as biological controls for Botrytis because of the common problem of fungicide resistance. Unfortunately, hyphal anastomosis is the only known mechanism of horizontal virus transmission and the large number of vegetative incompatibility groups in Botrytis is a potential constraint on the spread of an introduced virus. Although some Botrytis viruses, such as BVF and BVX, are known to have international distribution, there is a distinct lack of epidemiological data and the means of spread are unknown.
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Affiliation(s)
- Michael N Pearson
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand.
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Bryner SF, Rigling D, Brunner PC. Invasion history and demographic pattern of Cryphonectria hypovirus 1 across European populations of the chestnut blight fungus. Ecol Evol 2012; 2:3227-41. [PMID: 23301186 PMCID: PMC3539014 DOI: 10.1002/ece3.429] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 10/09/2012] [Accepted: 10/13/2012] [Indexed: 01/16/2023] Open
Abstract
We reconstructed the invasion history of the fungal virus Cryphonectria hypovirus 1 (CHV-1) in Europe, which infects the chestnut blight fungus Cryphonectria parasitica. The pattern of virus evolution was inferred based on nucleotide sequence variation from isolates sampled across a wide area in Europe at different points in time. Phylogeny and time estimates suggested that CHV-1 was introduced together with its fungal host to Europe and that it rapidly colonized the central range along the south facing slopes of the Alps and the north-east facing slopes of the Dinaric Alps. These central populations were the source for two waves of simultaneous invasions toward the southern Balkans and Turkey, as indicated by migration rates. Our results showed that the evolutionary scenarios for CHV-1 and C. parasitica were spatially congruent. As infection with CHV-1 reduces the pathogenicity of C. parasitica toward the chestnut tree, CHV-1 invasions of the newly established C. parasitica populations probably prevented the development of devastating chestnut blight epidemics in Europe. We propose that in this, and supposedly in other pathosystems, geographic, vegetation-related, demographic, economic, and political factors may help explain the correlated invasion pattern of a parasite and its host.
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Affiliation(s)
- Sarah F Bryner
- WSL Swiss Federal Research Institute CH-8903, Birmensdorf, Switzerland
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Variations in hypovirus interactions with the fungal-host RNA-silencing antiviral-defense response. J Virol 2012; 86:12933-9. [PMID: 22993160 DOI: 10.1128/jvi.00961-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hypoviruses Cryphonectria hypovirus 1 (CHV-1)/EP713, CHV-1/Euro7, and CHV-1/EP721, which infect the chestnut blight fungus Cryphonectria parasitica, differ in their degrees of virulence attenuation (hypovirulence), symptom expression, and viral RNA accumulation, even though they share between 90% and 99% amino acid sequence identity. In this report we examine whether this variability is influenced by interactions with the C. parasitica Dicer gene dcl2-dependent RNA-silencing antiviral defense response. The mild symptoms exhibited by strains infected with CHV-1/Euro7 and CHV-1/EP721 relative to those with severe hypovirus CHV-1/EP713 did not correlate with a higher induction of the RNA-silencing pathway. Rather, dcl2 transcripts accumulated to a higher level (∼8-fold) following infection by CHV-1/EP713 than following infection by CHV-1/Euro7 (1.2-fold) or CHV-1/EP721 (1.4-fold). The differences in dcl2 transcript accumulation in response to CHV-1/EP713 and CHV-1/EP721 were unrelated to the suppressor of RNA silencing, p29, encoded by the two viruses. Moreover, the coding strand viral RNA levels increased by 33-, 32-, and 16-fold for CHV-1/EP713, CHV-1/Euro7, and CHV-1/EP721, respectively, in Δdcl2 mutant strains. This indicates that a very robust antiviral RNA-silencing response was induced against all three viruses, even though significant differences in the levels of dcl2 transcript accumulation were observed. Unexpectedly, the severe debilitation previously reported for CHV-1/EP713-infected Δdcl2 mutant strains, and observed here for the CHV-1/Euro7-infected Δdcl2 mutant strains, was not observed with infection by CHV-1/EP721. By constructing chimeric viruses containing portions of CHV-1/EP713 and CHV-1/EP721, it was possible to map the region that is associated with the severe debilitation of the Δdcl2 mutant hosts to a 4.1-kb coding domain located in the central part of the CHV-1/EP713 genome.
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Wang J, Wang F, Feng Y, Mi K, Chen Q, Shang J, Chen B. Comparative vesicle proteomics reveals selective regulation of protein expression in chestnut blight fungus by a hypovirus. J Proteomics 2012; 78:221-30. [PMID: 22954595 DOI: 10.1016/j.jprot.2012.08.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2012] [Revised: 07/28/2012] [Accepted: 08/20/2012] [Indexed: 10/27/2022]
Abstract
The chestnut blight fungus (Cryphonectria parasitica) and hypovirus constitute a model system to study fungal pathogenesis and mycovirus-host interaction. Knowledge in this field has been gained largely from investigations at gene transcription level so far. Here we report a systematic analysis of the vesicle proteins of the host fungus with/without hypovirus infection. Thirty-three differentially expressed protein spots were identified in the purified vesicle protein samples by two-dimensional electrophoresis and mass spectrometry. Down-regulated proteins were mostly cargo proteins involved in primary metabolism and energy generation and up-regulated proteins were mostly vesicle associated proteins and ABC transporter. A virus-encoded protein p48 was found to have four forms with different molecular mass in vesicles from the virus-infected strain. While a few of the randomly selected differentially expressed proteins were in accordance with their transcription profiles, majority were not in agreement with their mRNA accumulation patterns, suggesting that an extensive post-transcriptional regulation may have occurred in the host fungus upon a hypovirus infection.
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Affiliation(s)
- Jinzi Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and Key Laboratory for Microbial and Plant Genetic Engineering, Ministry of Education, College of Life Science and Technology, Guangxi University, Nanning 530004, China
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Bryner SF, Rigling D. Virulence not only costs but also benefits the transmission of a fungal virus. Evolution 2012; 66:2540-50. [PMID: 22834751 DOI: 10.1111/j.1558-5646.2012.01637.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Current theory suggests that cost-benefit relationships govern the evolution of parasite virulence. The cost of virulence is expected to be high for fungal viruses, which are obligate parasites and completely dependent on their hosts. The majority of fungal viruses infect their hosts without any apparent symptoms. Cryphonectria hypovirus 1 (CHV-1), in contrast, is virulent and debilitates its host, Cryphonectria parasitica. However, the virulence of CHV-1 is associated with high costs for virus transmission, such as an attenuated fungal growth and reduced production of the fungal spores spreading the virus. In this study, we tested the hypothesis that virulence may not only have costs but also benefits for transmitting CHV-1 across vegetative incompatibility barriers between fungi. We investigated viruses with low, medium, and high virulence, and determined their transmission rate per host-to-host contact (transmissibility). The average transmission rate across all combinations tested was 53% for the most virulent virus, 37% for the virus with intermediate virulence, and 20% for the virus with lowest virulence. These results showed that increased virulence was strongly correlated with increased transmissibility, potentially counterbalancing virulence costs. This association of virulence and transmissibility may explain why CHV-1 spread widely and evolved higher virulence than most other fungal viruses.
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Mu R, Romero TA, Hanley KA, Dawe AL. Conserved and variable structural elements in the 5' untranslated region of two hypoviruses from the filamentous fungus Cryphonectria parasitica. Virus Res 2011; 161:203-8. [PMID: 21884737 DOI: 10.1016/j.virusres.2011.07.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 07/28/2011] [Accepted: 07/29/2011] [Indexed: 11/16/2022]
Abstract
Virulence-attenuating viruses (hypoviruses) of the filamentous fungus Cryphonectria parasitica, the causative agent of chestnut blight, have become a premier model for understanding the molecular biology of mycoviruses. However, a major gap exists in current understanding of structure and function of the untranslated regions (UTRs) of the hypovirus RNA genome, despite considerable evidence that secondary and tertiary UTR structure plays a crucial role in the control of translation and genome replication in other systems. In this study we have used structure prediction software coupled with RNase digestion studies to develop validated structural models for the 5' UTRs of the two best-characterized members of the Hypoviridae, CHV1-EP713 and CHV1-Euro7. These two hypovirus strains exhibit significant variation in virulence attenuation despite sharing >90% sequence identity. Our models reveal highly structured regions in the 5' UTR of both strains, with numerous stem-loops suggestive of internal ribosome entry sites. However, considerable differences in the size and complexity of structural elements exist between the two strains. These data will guide future, mutagenesis-based studies of the structural requirements for hypovirus genome replication and translation.
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Affiliation(s)
- Rong Mu
- Molecular Biology Program, New Mexico State University, Las Cruces, NM 88003, USA
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Popov AP, Belov AA, Ivanushkina NE, Tsvetkov IL, Konichev AS. Molecular genetic determinants of intraspecific polymorphism of the phytopathogenic fungus Cryphonectria parasitica. RUSS J GENET+ 2011. [DOI: 10.1134/s1022795411030112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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46
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Dawe AL, Mu R, Rivera G, Salamon JA. Molecular methods for studying the Cryphonectria parasitica - hypovirus experimental system. Methods Mol Biol 2011; 722:225-36. [PMID: 21590425 DOI: 10.1007/978-1-61779-040-9_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The interaction of the filamentous fungal plant pathogen Cryphonectria parasitica with its virulence-attenuating viruses provides a unique platform to explore the molecular biology and genetics of virus-host interactions. Following the development of transformation procedures for this fungus, subsequent advances include infectious cDNA clones of several members of the Hypoviridae and an imminently complete fungal genome project. Presented here are basic protocols for growth of the organism and the extraction of DNA, RNA, and protein. Additionally, two further protocols are provided for investigations of host protein phosphorylation and for viral genome secondary structure.
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Affiliation(s)
- Angus L Dawe
- Department of Biology and Molecular Biology Program, New Mexico State University, Las Cruces, NM, USA.
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Abstract
In contrast to viruses of plants and animals, viruses of fungi, mycoviruses, uniformly lack an extracellular phase to their replication cycle. The persistent, intracellular nature of the mycovirus life cycle presents technical challenges to experimental design. However, these properties, coupled with the relative simplicity and evolutionary position of the fungal host, also provide opportunities for examining fundamental aspects of virus-host interactions from a perspective that is quite different from that pertaining for most plant and animal virus infections. This chapter presents support for this view by describing recent advances in the understanding of antiviral defense responses against one group of mycoviruses for which many of the technical experimental challenges have been overcome, the hypoviruses responsible for hypovirulence of the chestnut blight fungus Cryphonectria parasitica. The findings reveal new insights into the induction and suppression of RNA silencing as an antiviral defense response and an unexpected role for RNA silencing in viral RNA recombination.
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Affiliation(s)
- Donald L Nuss
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland, USA
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Bryner SF, Rigling D. Temperature-dependent genotype-by-genotype interaction between a pathogenic fungus and its hyperparasitic virus. Am Nat 2010; 177:65-74. [PMID: 21117965 DOI: 10.1086/657620] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The outcome of host-parasite interactions may depend not only on the genotypes of the species involved but also on environmental factors. We used the fungus Cryphonectria parasitica, the causal agent of chestnut blight, and its hyperparasitic virus, Cryphonectria hypovirus-1 (CHV1), to test for genotype-by-genotype-by-environment interactions in a host-parasite system. In C. parasitica, infection with CHV1 induces a hypovirulent phenotype with reduced virulence toward the chestnut tree (Castanea spp.) and thus controls chestnut blight in many European regions. In contrast, uninfected virulent C. parasitica have nearly eradicated the American chestnut in North America. We applied a full factorial design and assessed the fungal growth and sporulation of four C. parasitica strains, uninfected and infected with each of the four known CHV1 subtypes, at 12°, 18°, 24°, and 30°C. We found a significant (P ≤ .00001) genotype-by-genotype-by-environment interaction, demonstrating the potential for a selection mosaic. As a consequence, different host and parasite genotypes would be selected under different climatic conditions, affecting the coevolutionary dynamics of the host-parasite interaction and the course of chestnut blight epidemics. Genotype-by-genotype-by-environment interactions are essential to take into account when designing biological control strategies.
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Affiliation(s)
- Sarah Franziska Bryner
- Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL), CH-8903 Birmensdorf, Switzerland.
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Fungi, Bacteria, and Viruses as Pathogens of the Fungal Community. Mycology 2009. [DOI: 10.1201/9781420027891.ch20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2023] Open
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A single Argonaute gene is required for induction of RNA silencing antiviral defense and promotes viral RNA recombination. Proc Natl Acad Sci U S A 2009; 106:17927-32. [PMID: 19822766 DOI: 10.1073/pnas.0907552106] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Dicer gene dcl2, required for the RNA silencing antiviral defense response in the chestnut blight fungus Cryphonectria parasitica, is inducible upon mycovirus infection and promotes viral RNA recombination. We now report that the antiviral defense response requires only one of the four C. parasitica Argonaute-like protein genes, agl2. The agl2 gene is required for the virus-induced increase in dcl2 transcript accumulation. Agl2 and dcl2 transcripts accumulated to much higher levels in response to hairpin RNA production or infection by a mutant CHV1-EP713 hypovirus lacking the suppressor of RNA silencing p29 than to wild-type CHV1-EP713. Similar results were obtained for an agl2-promoter/EGFP-reporter construct, indicating that p29-mediated repression of agl2 transcript accumulation is promoter-dependent. Significantly, the agl2 deletion mutant exhibited stable maintenance of non-viral sequences in recombinant hypovirus RNA virus vectors and the absence of hypovirus-defective interfering (DI) RNA production. These results establish a key role for an Argonaute gene in the induction of an RNA silencing antiviral defense response and the promotion of viral RNA recombination. They also provide evidence for a mechanism by which a virus-encoded RNA silencing suppressor represses the transcriptional induction of an RNA silencing component.
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