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Jiang Y, Liu X, Tian X, Zhou J, Wang Q, Wang B, Yu W, Jiang Y, Hsiang T, Qi X. RNA interference of Aspergillus flavus in response to Aspergillus flavus partitivirus 1 infection. Front Microbiol 2023; 14:1252294. [PMID: 38033556 PMCID: PMC10682719 DOI: 10.3389/fmicb.2023.1252294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 10/19/2023] [Indexed: 12/02/2023] Open
Abstract
RNA interference (RNAi) is one of the important defense responses against viral infection, but its mechanism and impact remain unclear in mycovirus infections. In our study, reverse genetics and virus-derived small RNA sequencing were used to show the antiviral responses of RNAi components in Aspergillus flavus infected with Aspergillus flavus partitivirus 1 (AfPV1). qRT-PCR revealed that AfPV1 infection induced the expression of the RNAi components in A. flavus compared with noninfected A. flavus. Knock mutants of each RNAi component were generated, but the mutants did not exhibit any obvious phenotypic changes compared with the A. flavus parental strain. However, after AfPV1 inoculation, production of AfPV1 was significantly less than in the parental strain. Furthermore, sporulation was greater in each AfPV1-infected mutant compared with the AfPV1-infected parental A. flavus. We also investigated the sensitivity of virus-free and AfPV1-infected RNAi mutants and the parental strain to cell wall stress, osmotic stress, genotoxic stress, and oxidative stress. The mutants of DCLs and AGOs infected by AfPV1 displayed more changes than RDRP mutants in response to the first three stresses. Small RNA sequencing analysis suggested that AfPV1 infection reduced the number of unique reads of sRNA in A. flavus, although there were many vsiRNA derived from the AfPV1 genome. GO term and KEGG pathway analyses revealed that the functions of sRNA affected by AfPV1 infection were closely related to vacuole production. These results provide a better understanding of the functional role of RNAi in the impact of AfPV1 on the hypovirulence of A. flavus.
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Affiliation(s)
- Yinhui Jiang
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Xiang Liu
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Xun Tian
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Jianhong Zhou
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Qinrong Wang
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Bi Wang
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Wenfeng Yu
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Yanping Jiang
- Department of Dermatology, The Affiliated Hospital, Guizhou Medical University, Guiyang, China
| | - Tom Hsiang
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
| | - Xiaolan Qi
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
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Sato Y, Suzuki N. Continued mycovirus discovery expanding our understanding of virus lifestyles, symptom expression, and host defense. Curr Opin Microbiol 2023; 75:102337. [PMID: 37343415 DOI: 10.1016/j.mib.2023.102337] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 06/23/2023]
Abstract
High-throughput sequencing technologies have greatly expanded the RNA virome in general and have led to an exponential increase in new fungal viruses, also known as mycoviruses. Mycoviruses are omnipresent in fungi and usually induce symptomless infections. Some mycoviruses infecting fungi pathogenic to plants, insects, and mammals are known to modify host virulence positively and negatively and attract particular interests. In addition, fungal viruses continue to provide intriguing research materials and themes that lead to discoveries of peculiar viruses as infectious entities and insights into virus evolution and diversity. In this review, we outline the diversity and neolifestyle of recently discovered fungal RNA viruses, and phenotypic alterations induced by them. Furthermore, we discuss recent advances in research regarding the fungal antiviral defense and viral counterdefense, which are closely associated with host phenotype alterations. We hope that this article will enhance understanding of the interesting and growing fungal virology field.
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Affiliation(s)
- Yukiyo Sato
- Institute for Plant Sciences, University of Cologne, Cologne, Germany
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chu-ou, Kurashiki, Okayama 710-0046, Japan.
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Li S, Zhu H, He Y, Hong N, Wang G, Wang L. BdCV1-Encoded P3 Silencing Suppressor Identification and Its Roles in Botryosphaeria dothidea, Causing Pear Ring Rot Disease. Cells 2023; 12:2386. [PMID: 37830600 PMCID: PMC10571871 DOI: 10.3390/cells12192386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 10/14/2023] Open
Abstract
Pear ring rot disease is an important branch disease, caused by Botryosphaeria dothidea. With the discovery of fungal viruses, the use of their attenuated properties for biological control provides a new strategy for the biological control of fungal disease. RNA silencing is a major antiviral defense mechanism in plants, insects, and fungi. Viruses encode and utilize RNA silencing suppressors to suppress host defenses. Previous studies revealed that Botryosphaeria dothidea chrysovirus 1 (BdCV1) exhibited weak pathogenicity and could activate host gene silencing by infecting B. dothidea. The aim of our study was to investigate whether BdCV1 can encode a silencing suppressor and what effect it has on the host. In this study, the capability of silencing inhibitory activity of four BdCV1-encoded proteins was analyzed, and the P3 protein was identified as a BdCV1 RNA silencing suppressor in the exotic host Nicotiana benthamiana line 16c. In addition, we demonstrated that P3 could inhibit local silencing, block systemic RNA silencing, and induce the necrosis reaction of tobacco leaves. Furthermore, overexpression of P3 could slow down the growth rate and reduce the pathogenicity of B. dothidea, and to some extent affect the expression level of RNA silencing components and virus-derived siRNAs (vsiRNAs). Combined with transcriptomic analysis, P3 had an effect on the gene expression and biological process of B. dothidea. The obtained results provide new theoretical information for further study of interaction between BdCV1 P3 as a potential silencing suppressor and B. dothidea.
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Affiliation(s)
- Shanshan Li
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
| | - Haodong Zhu
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
| | - Ying He
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
| | - Ni Hong
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
| | - Guoping Wang
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
| | - Liping Wang
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
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Khan HA, Nerva L, Bhatti MF. The good, the bad and the cryptic: The multifaceted roles of mycoviruses and their potential applications for a sustainable agriculture. Virology 2023; 585:259-269. [PMID: 37453341 DOI: 10.1016/j.virol.2023.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/05/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023]
Abstract
Mycoviruses are natural inhabitants of fungi and have been identified in almost all fungal taxonomic groups. Mycoviruses that infect phytopathogenic fungi are now becoming a hot research area due to their potential for the biocontrol of important plant pathogens. But, before considering a mycovirus for biocontrol, we should be fully aware of the effects it induces in a fungal host and its interactions with other viruses, fungal strains and even the host plants. Mycoviral infections are generally associated with different effects, ranging from hypovirulence to hypervirulence, but they can often be cryptic (latent infections). The cryptic lifestyle has been associated to many mycoviruses, but thanks to growing knowledge we are now aware that it is often associated to axenic conditions while the real effects can be observed only in nature. Other mycoviruses either promote (hypervirulence) or (hypovirulence) fungal pathogenicity by a strong impact on the fungal physiology or by blocking the production of toxins or effectors. Finally, indirect effects of mycoviral infections can also be provided to the plant that hosts the fungal isolate, highlighting not only their potential as direct biocontrol agents but also as priming agents for plant resilience to biotic and abiotic stresses. This review provides a broad overview of mycoviral interactions both with their hosts and with other mycoviruses, highlighting the most interesting examples. In contrast to what has been observed to date, we believe that the collective availability of these data will not only improve our understanding of mycoviruses, but also increase our confidence in considering them as alternative measures against fungal diseases to improve the sustainable production of food and feed commodities.
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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, 44000, Islamabad, Pakistan; Department of Biotechnology, University of Mianwali, Punjab, 42200, Pakistan
| | - Luca Nerva
- Research Centre for Viticulture and Enology, Council for Agricultural Research and Economics (CREA-VE), Via XXVIII Aprile, 31015, Conegliano, (TV), Italy.
| | - Muhammad Faraz Bhatti
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, 44000, Islamabad, Pakistan
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Wang P, Yang G, Lu H, Huang B. Infection with a novel polymycovirus enhances growth, conidiation and sensitivity to UV-B irradiation of the entomopathogenic fungus Metarhizium anisopliae. Front Microbiol 2023; 14:1214133. [PMID: 37469432 PMCID: PMC10352681 DOI: 10.3389/fmicb.2023.1214133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 06/14/2023] [Indexed: 07/21/2023] Open
Abstract
Metarhizium anisopliae is a well-studied entomopathogenic fungus that is widely used in biological control programs. The presence of polymycoviruses in this fungus is common, but their effects on fungal development and stress tolerance are not well understood. In this study, we report the discovery of a novel double-stranded RNA virus, named Metarhizium anisopliae polymycovirus 1 (MaPmV1), which comprises four dsRNAs ranging from 2.4 to 1.4 kbp in length. Phylogenetic analysis revealed that MaPmV1 belongs to the Polymycoviridae family. Biological comparison between MaPmV1-infected (Vi) and -free (Vf) isogenic lines showed that MaPmV1 remarkably enhances the growth rate and conidiation of the host fungus. The upregulation of growth- and conidiation-related genes in Vi strains supports this finding. In addition, MaPmV1 increases the sensitivity of the host to UV-B irradiation, which is evidenced by the downregulation of DNA damage repair genes in Vi strains. However, MaPmV1 does not appear to have any significant impact on the virulence of M. anisopliae. Furthermore, overexpression of individual viral proteins in M. anisopliae did not result in any significant phenotypic alterations, indicating that MaPmV1-mediated changes are not related to a single viral protein. Overall, our findings suggest that mycoviruses can be exploited to enhance fungal development in entomopathogenic fungi, which may lead to improved conidium production on a large scale.
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Affiliation(s)
- Ping Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Guogen Yang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
- School of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Hanwen Lu
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Bo Huang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
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6
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Wang P, Yang G, Shi N, Zhao C, Hu F, Coutts RHA, Kotta-Loizou I, Huang B. A novel partitivirus orchestrates conidiation, stress response, pathogenicity, and secondary metabolism of the entomopathogenic fungus Metarhizium majus. PLoS Pathog 2023; 19:e1011397. [PMID: 37216409 DOI: 10.1371/journal.ppat.1011397] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 05/01/2023] [Indexed: 05/24/2023] Open
Abstract
Mycoviruses are widely present in all major groups of fungi but those in entomopathogenic Metarhizium spp. remain understudied. In this investigation, a novel double-stranded (ds) RNA virus is isolated from Metarhizium majus and named Metarhizium majus partitivirus 1 (MmPV1). The complete genome sequence of MmPV1 comprises two monocistronic dsRNA segments (dsRNA 1 and dsRNA 2), which encode an RNA-dependent RNA polymerase (RdRp) and a capsid protein (CP), respectively. MmPV1 is classified as a new member of the genus Gammapartitivirus in the family Partitiviridae based on phylogenetic analysis. As compared to an MmPV1-free strain, two isogenic MmPV1-infected single-spore isolates were compromised in terms of conidiation, and tolerance to heat shock and UV-B irradiation, while these phenotypes were accompanied by transcriptional suppression of multiple genes involved in conidiation, heat shock response and DNA damage repair. MmPV1 attenuated fungal virulence since infection resulted in reduced conidiation, hydrophobicity, adhesion, and cuticular penetration. Additionally, secondary metabolites were significantly altered by MmPV1 infection, including reduced production of triterpenoids, and metarhizins A and B, and increased production of nitrogen and phosphorus compounds. However, expression of individual MmPV1 proteins in M. majus had no impact on the host phenotype, suggesting insubstantive links between defective phenotypes and a single viral protein. These findings indicate that MmPV1 infection decreases M. majus fitness to its environment and its insect-pathogenic lifestyle and environment through the orchestration of the host conidiation, stress tolerance, pathogenicity, and secondary metabolism.
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Affiliation(s)
- Ping Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Guogen Yang
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, School of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Najie Shi
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Cheng Zhao
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Fenglin Hu
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Robert H A Coutts
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Ioly Kotta-Loizou
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Bo Huang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
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7
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Kwon G, Yu J, Kim KH. Identifying transcription factors associated with Fusarium graminearum virus 2 accumulation in Fusarium graminearum by phenome-based investigation. Virus Res 2023; 326:199061. [PMID: 36738934 DOI: 10.1016/j.virusres.2023.199061] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/27/2023] [Accepted: 02/01/2023] [Indexed: 02/06/2023]
Abstract
Fusarium graminearum virus 2 (FgV2) infection induces phenotypic changes like reduction of growth rate and virulence with an alteration of the transcriptome, including various transcription factor (TFs) gene transcripts in Fusarium graminearum. Transcription factors are the primary regulator in many cellular processes and are significant in virus-host interactions. However, a detailed study about specific TFs to understand interactions between FgV2 and F. graminearum has yet to be conducted. We transferred FgV2 to a F. graminearum TF gene deletion mutant library to identify host TFs related to FgV2 infection. FgV2-infected TF mutants were classified into three groups depending on colony growth. The FgV2 accumulation level was generally higher in TF mutants showing more reduced growth. Among these FgV2-infected TF mutants, we found several possible TFs that might be involved in FgV2 accumulation, generation of defective interfering RNAs, and transcriptional regulation of FgDICER-2 and FgAGO-1 in response to virus infection. We also investigated the relation between FgV2 accumulation and production of reactive oxygen species (ROS) and DNA damage in fungal host cells by using DNA damage- or ROS-responsive TF deletion mutants. Our studies provide insights into the host factors related to FgV2 infection and bases for further investigation to understand interactions between FgV2 and F. graminearum.
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Affiliation(s)
- Gudam Kwon
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, South Korea
| | - Jisuk Yu
- Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, South Korea.
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, South Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, South Korea; Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, South Korea.
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Wang S, Ruan S, Zhang M, Nie J, Nzabanita C, Guo L. Interference of Small RNAs in Fusarium graminearum through FgGMTV1 Infection. J Fungi (Basel) 2022; 8:jof8121237. [PMID: 36547570 PMCID: PMC9781238 DOI: 10.3390/jof8121237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/06/2022] [Accepted: 11/11/2022] [Indexed: 11/24/2022] Open
Abstract
Small RNA (sRNA) plays a central role in RNA silencing in fungi. The genome of Fusarium graminearum gemytripvirus 1 (FgGMTV1) is comprised of three DNA segments: DNA-A, DNA-B, and DNA-C. DNA-A and DNA-B are associated with fungal growth and virulence reduction. To elucidate the role of RNA silencing during the interactions of fungi and viruses, the sRNA profiles of F. graminearum in association with FgGMTV1 were established, using an FgGMTV1-free library (S-S), a library for infection with the DNA-A and DNA-B segments (S-AB), and a library for infection with the DNA-A, DNA-B, and DNA-C segments (S-ABC). A large amount of virus-derived sRNA (vsiRNA) was detected in the S-AB and S-ABC libraries, accounting for 9.9% and 13.8% of the total sRNA, respectively, indicating that FgGMTV1 triggers host RNA silencing. The total numbers of sRNA reads differed among the three libraries, suggesting that FgGMTV1 infection interferes with host RNA silencing. In addition, the relative proportions of the different sRNA lengths were altered in the S-AB and S-ABC libraries. The genome distribution patterns of the mapping of vsiRNA to DNA-A and DNA-B in the S-AB and S-ABC libraries were also different. These results suggest the influence of DNA-C on host RNA silencing. Transcripts targeted by vsiRNAs were enriched in pathways that included flavin adenine dinucleotide binding, protein folding, and filamentous growth.
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Affiliation(s)
- Shuangchao Wang
- State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, 100193 Beijing, China
| | - Shaojian Ruan
- State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, 100193 Beijing, China
| | - Mingming Zhang
- Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium
| | - Jianhua Nie
- State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, 100193 Beijing, China
| | - Clement Nzabanita
- State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, 100193 Beijing, China
| | - Lihua Guo
- State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, 100193 Beijing, China
- Correspondence: ; Tel.: +86-01082105928
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Wang S, Zhang J, Nzabanita C, Zhang M, Nie J, Guo L. Fungal Virus, FgHV1-Encoded p20 Suppresses RNA Silencing through Single-Strand Small RNA Binding. J Fungi (Basel) 2022; 8:1171. [PMID: 36354938 PMCID: PMC9693516 DOI: 10.3390/jof8111171] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 11/03/2022] [Accepted: 11/03/2022] [Indexed: 10/14/2023] Open
Abstract
Fungal viruses are widespread in fungi infecting plants, insects and animals. High-throughput sequencing has rapidly led to the discovery of fungal viruses. However, the interactive exploration between fungi and viruses is relatively limited. RNA silencing is the fundamental antivirus pathway in fungi. Fusarium graminearum small RNA (sRNA) pattern was regulated by Fusarium graminearum hypovirus 1 (FgHV1) infection, indicating the activation of RNA silencing in virus defense. In this study, we focused on the function of an uncharacterized protein sized at 20 kD (p20) encoded by FgHV1. In the agro-infiltration assay, p20 was identified as a novel fungal RNA silencing suppressor. p20 can block systemic RNA silencing signals besides local RNA silencing suppression. We further elucidated the RNA silencing suppression mechanism of p20. The single-strand sRNA, instead of double-strand sRNA, can be incorporated by p20 in electrophoretic mobility shift assay. p20 binds sRNA originating from virus and non-virus sources in a non-sequence-specific manner. In addition, The F. graminearum 22 and 23-nt sRNA abundance and pathways related to RNA processing and redox regulation were regulated by p20. Our study revealed the first fungal virus-encoded RNA silencing suppressor with sRNA binding capability.
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Affiliation(s)
- Shuangchao Wang
- State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Jingze Zhang
- State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Clement Nzabanita
- State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Mingming Zhang
- Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium
| | - Jianhua Nie
- State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Lihua Guo
- State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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Rodriguez Coy L, Plummer KM, Khalifa ME, MacDiarmid RM. Mycovirus-encoded suppressors of RNA silencing: Possible allies or enemies in the use of RNAi to control fungal disease in crops. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:965781. [PMID: 37746227 PMCID: PMC10512228 DOI: 10.3389/ffunb.2022.965781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 09/21/2022] [Indexed: 09/26/2023]
Abstract
Plants, fungi, and many other eukaryotes have evolved an RNA interference (RNAi) mechanism that is key for regulating gene expression and the control of pathogens. RNAi inhibits gene expression, in a sequence-specific manner, by recognizing and deploying cognate double-stranded RNA (dsRNA) either from endogenous sources (e.g. pre-micro RNAs) or exogenous origin (e.g. viruses, dsRNA, or small interfering RNAs, siRNAs). Recent studies have demonstrated that fungal pathogens can transfer siRNAs into plant cells to suppress host immunity and aid infection, in a mechanism termed cross-kingdom RNAi. New technologies, based on RNAi are being developed for crop protection against insect pests, viruses, and more recently against fungal pathogens. One example, is host-induced gene silencing (HIGS), which is a mechanism whereby transgenic plants are modified to produce siRNAs or dsRNAs targeting key transcripts of plants, or their pathogens or pests. An alternative gene regulation strategy that also co-opts the silencing machinery is spray-induced gene silencing (SIGS), in which dsRNAs or single-stranded RNAs (ssRNAs) are applied to target genes within a pathogen or pest. Fungi also use their RNA silencing machinery against mycoviruses (fungal viruses) and mycoviruses can deploy virus-encoded suppressors of RNAi (myco-VSRs) as a counter-defence. We propose that myco-VSRs may impact new dsRNA-based management methods, resulting in unintended outcomes, including suppression of management by HIGS or SIGS. Despite a large diversity of mycoviruses being discovered using high throughput sequencing, their biology is poorly understood. In particular, the prevalence of mycoviruses and the cellular effect of their encoded VSRs are under-appreciated when considering the deployment of HIGS and SIGS strategies. This review focuses on mycoviruses, their VSR activities in fungi, and the implications for control of pathogenic fungi using RNAi.
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Affiliation(s)
- Lorena Rodriguez Coy
- Australian Research Council Research Hub for Sustainable Crop Protection, Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, VIC, Australia
| | - Kim M. Plummer
- Australian Research Council Research Hub for Sustainable Crop Protection, Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, VIC, Australia
| | - Mahmoud E. Khalifa
- Botany and Microbiology Department, Faculty of Science, Damietta University, Damietta, Egypt
| | - Robin M. MacDiarmid
- BioProtection, The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
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Kondo H, Botella L, Suzuki N. Mycovirus Diversity and Evolution Revealed/Inferred from Recent Studies. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:307-336. [PMID: 35609970 DOI: 10.1146/annurev-phyto-021621-122122] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
High-throughput virome analyses with various fungi, from cultured or uncultured sources, have led to the discovery of diverse viruses with unique genome structures and even neo-lifestyles. Examples in the former category include splipalmiviruses and ambiviruses. Splipalmiviruses, related to yeast narnaviruses, have multiple positive-sense (+) single-stranded (ss) RNA genomic segments that separately encode the RNA-dependent RNA polymerase motifs, the hallmark of RNA viruses (members of the kingdom Orthornavirae). Ambiviruses appear to have an undivided ssRNA genome of 3∼5 kb with two large open reading frames (ORFs) separated by intergenic regions. Another narna-like virus group has two fully overlapping ORFs on both strands of a genomic segment that span more than 90% of the genome size. New virus lifestyles exhibited by mycoviruses include the yado-kari/yado-nushi nature characterized by the partnership between the (+)ssRNA yadokarivirus and an unrelated dsRNA virus (donor of the capsid for the former) and the hadaka nature of capsidless 10-11 segmented (+)ssRNA accessible by RNase in infected mycelial homogenates. Furthermore, dsRNA polymycoviruses with phylogenetic affinity to (+)ssRNA animal caliciviruses have been shown to be infectious as dsRNA-protein complexes or deproteinized naked dsRNA. Many previous phylogenetic gaps have been filled by recently discovered fungal and other viruses, which haveprovided interesting evolutionary insights. Phylogenetic analyses and the discovery of natural and experimental cross-kingdom infections suggest that horizontal virus transfer may have occurred and continue to occur between fungi and other kingdoms.
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Affiliation(s)
- Hideki Kondo
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan;
| | - Leticia Botella
- Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University, Brno, Czech Republic
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan;
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Li K, Liu D, Pan X, Yan S, Song J, Liu D, Wang Z, Xie Y, Dai J, Liu J, Li H, Zhang X, Gao F. Deoxynivalenol Biosynthesis in Fusarium pseudograminearum Significantly Repressed by a Megabirnavirus. Toxins (Basel) 2022; 14:toxins14070503. [PMID: 35878241 PMCID: PMC9324440 DOI: 10.3390/toxins14070503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/08/2022] [Accepted: 07/15/2022] [Indexed: 01/27/2023] Open
Abstract
Deoxynivalenol (DON) is a mycotoxin widely detected in cereal products contaminated by Fusarium. Fusarium pseudograminearum megabirnavirus 1 (FpgMBV1) is a double-stranded RNA virus infecting Fusarium pseudograminearum. In this study, it was revealed that the amount of DON in F. pseudograminearum was significantly suppressed by FpgMBV1 through a high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) assay. A total of 2564 differentially expressed genes were identified by comparative transcriptomic analysis between the FpgMBV1-containing F. pseudograminearum strain FC136-2A and the virus-free strain FC136-2A-V-. Among them, 1585 genes were up-regulated and 979 genes were down-regulated. Particularly, the expression of 12 genes (FpTRI1, FpTRI3, FpTRI4, FpTRI5, FpTRI6, FpTRI8, FpTRI10, FpTRI11, FpTRI12, FpTRI14, FpTRI15, and FpTRI101) in the trichothecene biosynthetic (TRI) gene cluster was significantly down-regulated. Specific metabolic and transport processes and pathways including amino acid and lipid metabolism, ergosterol metabolic and biosynthetic processes, carbohydrate metabolism, and biosynthesis were regulated. These results suggest an unrevealing mechanism underlying the repression of DON and TRI gene expression by the mycovirus FpgMBV1, which would provide new methods in the detoxification of DON and reducing the yield loss in wheat.
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Affiliation(s)
- Ke Li
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
| | - Dongmei Liu
- Institute of Agricultural Quality Standards and Testing Technology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China; (D.L.); (J.L.)
| | - Xin Pan
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
| | - Shuwei Yan
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
| | - Jiaqing Song
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
| | - Dongwei Liu
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
| | - Zhifang Wang
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
| | - Yuan Xie
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
| | - Junli Dai
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
| | - Jihong Liu
- Institute of Agricultural Quality Standards and Testing Technology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China; (D.L.); (J.L.)
| | - Honglian Li
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
| | - Xiaoting Zhang
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
- Correspondence: (X.Z.); (F.G.)
| | - Fei Gao
- Department of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China; (K.L.); (X.P.); (S.Y.); (J.S.); (D.L.); (Z.W.); (Y.X.); (J.D.); (H.L.)
- Correspondence: (X.Z.); (F.G.)
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Shimura H, Kim H, Matsuzawa A, Akino S, Masuta C. Coat protein of partitiviruses isolated from mycorrhizal fungi functions as an RNA silencing suppressor in plants and fungi. Sci Rep 2022; 12:7855. [PMID: 35551196 PMCID: PMC9098641 DOI: 10.1038/s41598-022-11403-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 04/19/2022] [Indexed: 12/11/2022] Open
Abstract
Orchid seeds depend on colonization by orchid mycorrhizal (OM) fungi for their germination; therefore, the orchids and OM fungi have long maintained a close relationship (e.g., formation of the hyphal mass structure, peloton) during their evolution. In the present study, we isolated new partitiviruses from OM fungi; partitivirus were separately found in different subcultures from the same fungi. Partitiviruses have been believed to lack an RNA silencing suppressor (RSS), which is generally associated with viral pathogenicity, because most partitiviruses isolated so far are latent in both plants and fungi. However, we found that the coat protein (CP) of our partitiviruses indeed had RSS activity, which differed among the virus isolates from OM fungi; one CP showed RSS activity in both plants and fungi, while another CP showed no activity. The family Partitiviridae include viruses isolated from plants and fungi, and it has been suggested that these viruses may occasionally be transmitted between plant and fungal hosts. Given that there are several reports showing that viruses can adapt to nonhost using strong RSS, we here discussed the idea that partitiviruses may be better able to migrate between the orchid and fungus probably through the pelotons formed in the orchid cells, if host RNA silencing is suppressed by partitivirus RSS.
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Affiliation(s)
- Hanako Shimura
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, 060-8589, Japan.
| | - Hangil Kim
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, 060-8589, Japan
| | - Akihiko Matsuzawa
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, 060-8589, Japan
| | - Seishi Akino
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, 060-8589, Japan
| | - Chikara Masuta
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, 060-8589, Japan.
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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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15
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Yu J, Kim KH. A Phenome-Wide Association Study of the Effects of Fusarium graminearum Transcription Factors on Fusarium Graminearum Virus 1 Infection. Front Microbiol 2021; 12:622261. [PMID: 33643250 PMCID: PMC7904688 DOI: 10.3389/fmicb.2021.622261] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/07/2021] [Indexed: 11/13/2022] Open
Abstract
The Fusarium graminearum virus 1 (FgV1) causes noticeable phenotypic changes such as reduced mycelial growth, increase pigmentation, and reduced pathogenicity in its host fungi, Fusarium graminearum. Previous study showed that the numerous F. graminearum genes including regulatory factors were differentially expressed upon FgV1 infection, however, we have limited knowledge on the effect(s) of specific transcription factor (TF) during FgV1 infection in host fungus. Using gene-deletion mutant library of 657 putative TFs in F. graminearum, we transferred FgV1 by hyphal anastomosis to screen transcription factors that might be associated with viral replication or symptom induction. FgV1-infected TF deletion mutants were divided into three groups according to the mycelial growth phenotype compare to the FgV1-infected wild-type strain (WT-VI). The FgV1-infected TF deletion mutants in Group 1 exhibited slow or weak mycelial growth compare to that of WT-VI on complete medium at 5 dpi. In contrast, Group 3 consists of virus-infected TF deletion mutants showing faster mycelial growth and mild symptom compared to that of WT-VI. The hyphal growth of FgV1-infected TF deletion mutants in Group 2 was not significantly different from that of WT-VI. We speculated that differences of mycelial growth among the FgV1-infected TF deletion mutant groups might be related with the level of FgV1 RNA accumulations in infected host fungi. By conducting real-time quantitative reverse transcription polymerase chain reaction, we observed close association between FgV1 RNA accumulation and phenotypic differences of FgV1-infected TF deletion mutants in each group, i.e., increased and decreased dsRNA accumulation in Group 1 and Group 3, respectively. Taken together, our analysis provides an opportunity to identify host's regulator(s) of FgV1-triggered signaling and antiviral responses and helps to understand complex regulatory networks between FgV1 and F. graminearum interaction.
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Affiliation(s)
- Jisuk Yu
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea
| | - Kook-Hyung Kim
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea.,Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul, South Korea.,Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
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16
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Identification of an RNA Silencing Suppressor Encoded by a Symptomless Fungal Hypovirus, Cryphonectria Hypovirus 4. BIOLOGY 2021; 10:biology10020100. [PMID: 33572564 PMCID: PMC7912522 DOI: 10.3390/biology10020100] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 01/28/2021] [Indexed: 12/14/2022]
Abstract
Simple Summary Host antiviral defense/viral counter-defense is an interesting topic in modern virology. RNA silencing is the primary antiviral mechanism in insects, plants, and fungi, while viruses encode and utilize RNA silencing suppressors against the host defense. Hypoviruses are positive-sense single-stranded RNA viruses with phylogenetic affinity to the picorna-like supergroup, including animal poliovirus and plant potyvirus. The prototype hypovirus Cryphonectria hypovirus 1, CHV1, is one of the best-studied fungal viruses. It is known to induce hypovirulence in the chestnut blight fungus, Cryphonectria parasitica, and encode an RNA silencing suppressor. CHV4 is another hypovirus asymptomatically that infects the same host fungus. This study shows that the N-terminal portion of the CHV4 polyprotein, termed p24, is a protease that autocatalytically cleaves itself from the rest of the viral polyprotein, and functions as an antiviral RNA silencing suppressor. Abstract Previously, we have reported the ability of a symptomless hypovirus Cryphonectria hypovirus 4 (CHV4) of the chestnut blight fungus to facilitate stable infection by a co-infecting mycoreovirus 2 (MyRV2)—likely through the inhibitory effect of CHV4 on RNA silencing (Aulia et al., Virology, 2019). In this study, the N-terminal portion of the CHV4 polyprotein, termed p24, is identified as an autocatalytic protease capable of suppressing host antiviral RNA silencing. Using a bacterial expression system, CHV4 p24 is shown to cleave autocatalytically at the di-glycine peptide (Gly214-Gly215) of the polyprotein through its protease activity. Transgenic expression of CHV4 p24 in Cryphonectria parasitica suppresses the induction of one of the key genes of the antiviral RNA silencing, dicer-like 2, and stabilizes the infection of RNA silencing-susceptible virus MyRV2. This study shows functional similarity between CHV4 p24 and its homolog p29, encoded by the symptomatic prototype hypovirus CHV1.
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Heo JI, Yu J, Choi H, Kim KH. The Signatures of Natural Selection and Molecular Evolution in Fusarium graminearum Virus 1. Front Microbiol 2020; 11:600775. [PMID: 33281800 PMCID: PMC7688778 DOI: 10.3389/fmicb.2020.600775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/27/2020] [Indexed: 11/21/2022] Open
Abstract
Fusarium graminearum virus 1 (FgV1) is a positive-sense ssRNA virus that confers hypovirulence in its fungal host, Fusarium graminearum. Like most mycoviruses, FgV1 exists in fungal cells, lacks an extracellular life cycle, and is therefore transmitted during sporulation or hyphal anastomosis. To understand FgV1 evolution and/or adaptation, we conducted mutation accumulation (MA) experiments by serial passage of FgV1 alone or with FgV2, 3, or 4 in F. graminearum. We expected that the effects of positive selection would be highly limited because of repeated bottleneck events. To determine whether selection on the virus was positive, negative, or neutral, we assessed both the phenotypic traits of the host fungus and the RNA sequences of FgV1. We inferred that there was positive selection on beneficial mutations in FgV1 based on the ratio of non-synonymous to synonymous substitutions (dN/dS), on the ratio of radical to conservation amino acid replacements (pNR/pNC), and by changes in the predicted protein structures. In support of this inference, we found evidence of positive selection only in the open reading frame 4 (ORF4) protein of DK21/FgV1 (MA line 1); mutations at amino acids 163A and 289H in the ORF4 of MA line 1 affected the entire structure of the protein predicted to be under positive selection. We also found, however, that deleterious mutations were a major driving force in viral evolution during serial passages. Linear relationships between changes in viral fitness and the number of mutations in each MA line demonstrated that some deleterious mutations resulted in fitness decline. Several mutations in MA line 1 were not shared with any of the other four MA lines (PH-1/FgV1, PH-1/FgV1 + 2, PH-1/FgV1 + 3, and PH-1/FgV1 + 4). This suggests that evolutionary pathways of the virus could differ with respect to hosts and also with respect to co-infecting viruses. The data also suggested that the differences among MA lines might also be explained by mutational robustness and other unidentified factors. Additional research is needed to clarify the effects of virus co-infection on the adaptation or evolution of FgV1 to its environments.
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Affiliation(s)
- Jeong-In Heo
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Jisuk Yu
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea
| | - Hoseong Choi
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.,Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea.,Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
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Honda S, Eusebio-Cope A, Miyashita S, Yokoyama A, Aulia A, Shahi S, Kondo H, Suzuki N. Establishment of Neurospora crassa as a model organism for fungal virology. Nat Commun 2020; 11:5627. [PMID: 33159072 PMCID: PMC7648066 DOI: 10.1038/s41467-020-19355-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 10/08/2020] [Indexed: 01/07/2023] Open
Abstract
The filamentous fungus Neurospora crassa is used as a model organism for genetics, developmental biology and molecular biology. Remarkably, it is not known to host or to be susceptible to infection with any viruses. Here, we identify diverse RNA viruses in N. crassa and other Neurospora species, and show that N. crassa supports the replication of these viruses as well as some viruses from other fungi. Several encapsidated double-stranded RNA viruses and capsid-less positive-sense single-stranded RNA viruses can be experimentally introduced into N. crassa protoplasts or spheroplasts. This allowed us to examine viral replication and RNAi-mediated antiviral responses in this organism. We show that viral infection upregulates the transcription of RNAi components, and that Dicer proteins (DCL-1, DCL-2) and an Argonaute (QDE-2) participate in suppression of viral replication. Our study thus establishes N. crassa as a model system for the study of host-virus interactions. The fungus Neurospora crassa is a model organism for the study of various biological processes, but it is not known to be infected by any viruses. Here, Honda et al. identify RNA viruses that infect N. crassa and examine viral replication and RNAi-mediated antiviral responses, thus establishing this fungus as a model for the study of host-virus interactions.
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Affiliation(s)
- Shinji Honda
- Faculty of Medical Sciences, University of Fukui, Fukui, 910-1193, Japan
| | - Ana Eusebio-Cope
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Shuhei Miyashita
- Graduate School of Agricultural Science, Tohoku University, 468-1, Aramaki-Aza- Aoba, Sendai, 980-0845, Japan
| | - Ayumi Yokoyama
- Faculty of Medical Sciences, University of Fukui, Fukui, 910-1193, Japan
| | - Annisa Aulia
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Sabitree Shahi
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Hideki Kondo
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan.
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19
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Zhang L, Chen X, Bhattacharjee P, Shi Y, Guo L, Wang S. Molecular Characterization of a Novel Strain of Fusarium graminearum Virus 1 Infecting Fusarium graminearum. Viruses 2020; 12:v12030357. [PMID: 32213895 PMCID: PMC7150806 DOI: 10.3390/v12030357] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/22/2020] [Accepted: 03/23/2020] [Indexed: 01/28/2023] Open
Abstract
Fungal viruses (mycoviruses) have attracted more attention for their possible hypovirulence (attenuation of fungal virulence) trait, which may be developed as a biocontrol agent of plant pathogenic fungi. However, most discovered mycoviruses are asymptomatic in their hosts. In most cases, mycovirus hypovirulent factors have not been explored clearly. In this study, we characterized a ssRNA mycovirus in Fusarium graminearum strain HB56-9. The complete nucleotide genome was obtained by combining random sequencing and rapid amplification of cDNA ends (RACE). The full genome was 6621-nucleotides long, excluding the poly(A) tail. The mycovirus was quite interesting because it shared 95.91% nucleotide identities with previously reported Fusarium graminearum virus 1 strain DK21 (FgV1-DK21), while the colony morphology of their fungal hosts on PDA plates were very different. The novel virus was named Fusarium graminearum virus 1 Chinese isolate (FgV1-ch). Like FgV1-DK21, FgV1-ch also contains four putative open reading frames (ORFs), including one long and three short ORFs. A phylogenetic analysis indicated that FgV1-ch is clustered into a proposed family Fusariviridae. FgV1-ch, unlike FgV1-DK21, had mild or no effects on host mycelial growth, spore production and virulence. The nucleotide differences between FgV1-ch and FgV1-DK21 will help to elucidate the hypovirulence determinants during mycovirus–host interaction.
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Affiliation(s)
- Lihang Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (L.Z.); (X.C.); (P.B.); (L.G.)
| | - Xiaoguang Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (L.Z.); (X.C.); (P.B.); (L.G.)
| | - Pallab Bhattacharjee
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (L.Z.); (X.C.); (P.B.); (L.G.)
| | - Yue Shi
- Agricultural Trade Promotion Center, Ministry of Agriculture and Rural Affairs, Beijing 100125, China;
| | - Lihua Guo
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (L.Z.); (X.C.); (P.B.); (L.G.)
| | - Shuangchao Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (L.Z.); (X.C.); (P.B.); (L.G.)
- Correspondence:
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20
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Abstract
In this review, we discuss recent studies of the interaction between Fusarium graminearum viruses (FgVs) and the fungal host, Fusarium graminearum. Comprehensive transcriptome and proteome analyses have shown changes in the expression of host genes in response to infection by diverse FgVs. Using omics data and reverse genetics, researchers have determined the effects of some fungal host proteins (including FgHex1, FgHal2, FgSwi6, and vr1) on virus accumulation, virus transmission, and host symptom development. Recent reports have revealed the functions of the RNAi component in F. graminearum and the functional redundancy of FgDICERs and FgAGOs in the antiviral defense response against different FgV infections. Studies have also documented a unique mechanism used by FgV1 to overcome the antiviral response of the fungal host.
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