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Butkovic A, Ellis TJ, Gonzalez R, Jaegle B, Nordborg M, Elena SF. Genetic basis of Arabidopsis thaliana responses to infection by naïve and adapted isolates of turnip mosaic virus. eLife 2024; 12:RP89749. [PMID: 38240739 PMCID: PMC10945600 DOI: 10.7554/elife.89749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024] Open
Abstract
Plant viruses account for enormous agricultural losses worldwide, and the most effective way to combat them is to identify genetic material conferring plant resistance to these pathogens. Aiming to identify genetic associations with responses to infection, we screened a large panel of Arabidopsis thaliana natural inbred lines for four disease-related traits caused by infection by A. thaliana-naïve and -adapted isolates of the natural pathogen turnip mosaic virus (TuMV). We detected a strong, replicable association in a 1.5 Mb region on chromosome 2 with a 10-fold increase in relative risk of systemic necrosis. The region contains several plausible causal genes as well as abundant structural variation, including an insertion of a Copia transposon into a Toll/interleukin receptor (TIR-NBS-LRR) coding for a gene involved in defense, that could be either a driver or a consequence of the disease-resistance locus. When inoculated with TuMV, loss-of-function mutant plants of this gene exhibited different symptoms than wild-type plants. The direction and severity of symptom differences depended on the adaptation history of the virus. This increase in symptom severity was specific for infections with the adapted isolate. Necrosis-associated alleles are found worldwide, and their distribution is consistent with a trade-off between resistance during viral outbreaks and a cost of resistance otherwise, leading to negative frequency-dependent selection.
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Affiliation(s)
- Anamarija Butkovic
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-Universitat de València, Parc Científic UVValènciaSpain
| | - Thomas James Ellis
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter, Doktor-Bohr-GasseViennaAustria
| | - Ruben Gonzalez
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-Universitat de València, Parc Científic UVValènciaSpain
| | - Benjamin Jaegle
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter, Doktor-Bohr-GasseViennaAustria
| | - Magnus Nordborg
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter, Doktor-Bohr-GasseViennaAustria
| | - Santiago F Elena
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-Universitat de València, Parc Científic UVValènciaSpain
- The Santa Fe InstituteSanta FeUnited States
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Tu CW, Huang YW, Lee CW, Kuo SY, Lin NS, Hsu YH, Hu CC. Argonaute 5-mediated antiviral defense and viral counter-defense in Nicotiana benthamiana. Virus Res 2023; 334:199179. [PMID: 37481165 PMCID: PMC10405324 DOI: 10.1016/j.virusres.2023.199179] [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: 06/08/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 07/24/2023]
Abstract
The argonaute (AGO) family proteins play a crucial role in preventing viral invasions through the plant antiviral RNA silencing pathway, with distinct AGO proteins recruited for specific antiviral mechanisms. Our previous study revealed that Nicotiana benthamiana AGO5 (NbAGO5) expression was significantly upregulated in response to bamboo mosaic virus (BaMV) infection. However, the roles of NbAGO5 in antiviral mechanisms remained to be explored. In this research, we examined the antiviral functions of NbAGO5 in the infections of different viruses. It was found that the accumulation of NbAGO5 was induced not only at the RNA but also at the protein level following the infections of BaMV, potato virus X (PVX), tobacco mosaic virus (TMV), and cucumber mosaic virus (CMV) in N. benthamiana. To explore the antiviral mechanism and regulatory function of NbAGO5, we generated NbAGO5 overexpression (OE-NbAGO5) and knockout (nbago5) transgenic N. benthamiana lines. Our findings reveal that NbAGO5 provides defense against BaMV, PVX, TMV, and a mutant CMV deficient in 2b gene, but not against the wild-type CMV and turnip mosaic virus (TuMV). Through affinity purification and small RNA northern blotting, we demonstrated that NbAGO5 exerts its antiviral function by binding to viral small interfering RNAs (vsiRNAs). Moreover, we observed that CMV 2b and TuMV HC-Pro interact with NbAGO5, triggering its degradation via the 26S proteasome and autophagy pathways, thereby allowing these viruses to overcome NbAGO5-mediated defense. In addition, TuMV HC-Pro provides another line of counter-defense by interfering with vsiRNA binding by NbAGO5. Our study provides further insights into the antiviral RNA interference mechanism and the complex interplay between NbAGO5 and plant viruses.
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Affiliation(s)
- Chin-Wei Tu
- PhD Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung 40227, Taiwan
| | - Ying-Wen Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan; Advanced Plant Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan
| | - Chin-Wei Lee
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Song-Yi Kuo
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore
| | - Na-Sheng Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan; Advanced Plant Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan
| | - Chung-Chi Hu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan; Advanced Plant Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan.
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3
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Zhao L, Chen Y, Xiao X, Gao H, Cao J, Zhang Z, Guo Z. AGO2a but not AGO2b mediates antiviral defense against infection of wild-type cucumber mosaic virus in tomato. HORTICULTURE RESEARCH 2023; 10:uhad043. [PMID: 37188058 PMCID: PMC10177002 DOI: 10.1093/hr/uhad043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 03/05/2023] [Indexed: 05/17/2023]
Abstract
Evolutionarily conserved antiviral RNA interference (RNAi) mediates a primary antiviral innate immunity preventing infection of broad-spectrum viruses in plants. However, the detailed mechanism in plants is still largely unknown, especially in important agricultural crops, including tomato. Varieties of pathogenic viruses evolve to possess viral suppressors of RNA silencing (VSRs) to suppress antiviral RNAi in the host. Due to the prevalence of VSRs, it is still unknown whether antiviral RNAi truly functions to prevent invasion by natural wild-type viruses in plants and animals. In this research, for the first time we applied CRISPR-Cas9 to generate ago2a, ago2b, or ago2ab mutants for two differentiated Solanum lycopersicum AGO2s, key effectors in antiviral RNAi. We found that AGO2a but not AGO2b was significantly induced to inhibit the propagation of not only VSR-deficient Cucumber mosaic virus (CMV) but also wild-type CMV-Fny in tomato; however, neither AGO2a nor AGO2b regulated disease induction after infection with either virus. Our findings firstly reveal a prominent role of AGO2a in antiviral RNAi innate immunity in tomato and demonstrate that antiviral RNAi evolves to defend against infection of natural wild-type CMV-Fny in tomato. However, AGO2a-mediated antiviral RNAi does not play major roles in promoting tolerance of tomato plants to CMV infection for maintaining health.
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Affiliation(s)
| | | | - Xingming Xiao
- Vector-borne Virus Research Center, State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002 China
| | - Haiying Gao
- Vector-borne Virus Research Center, State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002 China
| | - Jiamin Cao
- Vector-borne Virus Research Center, State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002 China
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Ding SW. Transgene Silencing, RNA Interference, and the Antiviral Defense Mechanism Directed by Small Interfering RNAs. PHYTOPATHOLOGY 2023; 113:616-625. [PMID: 36441873 DOI: 10.1094/phyto-10-22-0358-ia] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
One important discovery in plant pathology over recent decades is the natural antiviral defense mechanism mediated by RNA interference (RNAi). In antiviral RNAi, virus infection triggers Dicer processing of virus-specific double-stranded RNA into small interfering RNAs (siRNAs). Frequently, further amplified by host enzyme and cofactors, these virus-derived siRNAs direct specific virus clearance in an Argonaute protein-containing effector complex. The siRNAs derived from viruses and viroids accumulate to very high levels during infection. Because they overlap extensively in nucleotide sequence, this allows for deep sequencing and bioinformatics assembly of total small RNAs for rapid discovery and identification of viruses and viroids. Antiviral RNAi acts as the primary defense mechanism against both RNA and DNA viruses in plants, yet viruses still successfully infect plants. They do so because all currently recognized plant viruses combat the RNAi response by encoding at least one protein as a viral suppressor of RNAi (VSR) required for infection, even though plant viruses have small genome sizes with a limited coding capacity. This review article will recapitulate the key findings that have revealed the genetic pathway for the biogenesis and antiviral activity of viral siRNAs and the specific role of VSRs in infection by antiviral RNAi suppression. Moreover, early pioneering studies on transgene silencing, RNAi, and virus-plant/virus-virus interactions paved the road to the discovery of antiviral RNAi.
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Affiliation(s)
- Shou-Wei Ding
- Department of Microbiology & Plant Pathology and Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA
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5
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Pouclet A, Gagliardi D, Garcia D. No-go decay as a novel route to restrict viral infection in plants. MOLECULAR PLANT 2023; 16:509-510. [PMID: 36740835 DOI: 10.1016/j.molp.2023.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/01/2023] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Affiliation(s)
- Aude Pouclet
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Dominique Gagliardi
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Damien Garcia
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France.
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Hong SF, Fang RY, Wei WL, Jirawitchalert S, Pan ZJ, Hung YL, Pham TH, Chiu YH, Shen TL, Huang CK, Lin SS. Development of an assay system for the analysis of host RISC activity in the presence of a potyvirus RNA silencing suppressor, HC-Pro. Virol J 2023; 20:10. [PMID: 36650505 PMCID: PMC9844029 DOI: 10.1186/s12985-022-01956-2] [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: 10/21/2022] [Accepted: 12/18/2022] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND To investigate the mechanism of RNA silencing suppression, the genetic transformation of viral suppressors of RNA silencing (VSRs) in Arabidopsis integrates ectopic VSR expression at steady state, which overcomes the VSR variations caused by different virus infections or limitations of host range. Moreover, identifying the insertion of the transgenic VSR gene is necessary to establish a model transgenic plant for the functional study of VSR. METHODS Developing an endogenous AGO1-based in vitro RNA-inducing silencing complex (RISC) assay prompts further investigation into VSR-mediated suppression. Three P1/HC-Pro plants from turnip mosaic virus (TuMV) (P1/HC-ProTu), zucchini yellow mosaic virus (ZYMV) (P1/HC-ProZy), and tobacco etch virus (TEV) (P1/HC-ProTe) were identified by T-DNA Finder and used as materials for investigations of the RISC cleavage efficiency. RESULTS Our results indicated that the P1/HC-ProTu plant has slightly lower RISC activity than P1/HC-ProZy plants. In addition, the phenomena are consistent with those observed in TuMV-infected Arabidopsis plants, which implies that HC-ProTu could directly interfere with RISC activity. CONCLUSIONS In this study, we demonstrated the application of various plant materials in an in vitro RISC assay of VSR-mediated RNA silencing suppression.
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Affiliation(s)
- Syuan-Fei Hong
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Ru-Ying Fang
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Wei-Lun Wei
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Supidcha Jirawitchalert
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Zhao-Jun Pan
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Yu-Ling Hung
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Thanh Ha Pham
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Yen-Hsin Chiu
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan ,grid.453140.70000 0001 1957 0060Seed Improvement and Propagation Station, Council of Agriculture, Taichung, 427 Taiwan
| | - Tang-Long Shen
- grid.19188.390000 0004 0546 0241Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, 106 Taiwan ,grid.19188.390000 0004 0546 0241Center of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Chien-Kang Huang
- Department of Computer Science and Information Engineering, National Taiwan University, Taipei, 106, Taiwan.
| | - Shih-Shun Lin
- Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan. .,Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan. .,Center of Biotechnology, National Taiwan University, Taipei, 106, Taiwan.
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Komatsu K, Hammond J. Plantago asiatica mosaic virus: An emerging plant virus causing necrosis in lilies and a new model RNA virus for molecular research. MOLECULAR PLANT PATHOLOGY 2022; 23:1401-1414. [PMID: 35856603 PMCID: PMC9452766 DOI: 10.1111/mpp.13243] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 06/01/2023]
Abstract
TAXONOMY Plantago asiatica mosaic virus belongs to the genus Potexvirus in the family Alphaflexiviridae of the order Tymovirales. VIRION AND GENOME PROPERTIES Plantago asiatica mosaic virus (PlAMV) has flexuous virions of approximately 490-530 nm in length and 10-15 nm in width. The genome of PlAMV consists of a single-stranded, positive-sense RNA of approximately 6.13 kb. It contains five open reading frames (ORFs 1-5), encoding a putative viral polymerase (RdRp), movement proteins (triple gene block proteins, TGBp1-3), and coat protein (CP), respectively. HOST RANGE PlAMV has an exceptionally wide host range and has been isolated from various wild plants, including Plantago asiatica, Nandina domestica, Rehmannia glutinosa, and other weed plants. Experimentally PlAMV can infect many plant species including Nicotiana benthamiana and Arabidopsis thaliana. It also infects ornamental lilies and frequently causes severe necrotic symptoms. However, host range varies depending on isolates, which show significant biological diversity within the species. GENOME DIVERSITY PlAMV can be separated into five clades based on phylogenetic analyses; nucleotide identities are significantly low between isolates in the different clades. TRANSMISSION PlAMV is not reported to be transmitted by biological vectors. Virions of PlAMV are quite stable and it can be transmitted efficiently by mechanical contact. DISEASE SYMPTOMS PlAMV causes red-rusted systemic necrosis in ornamental lilies, but it shows much weaker, if any, symptoms in wild plants such as P. asiatica. CONTROL Control of the disease caused by PlAMV is based mainly on rapid diagnosis and elimination of the infected bulbs or plants.
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Affiliation(s)
- Ken Komatsu
- Graduate School of AgricultureTokyo University of Agriculture and Technology (TUAT)FuchuJapan
| | - John Hammond
- US Department of AgricultureAgricultural Research Service (USDA‐ARS)BeltsvilleMarylandUSA
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Determinants of Virus Variation, Evolution, and Host Adaptation. Pathogens 2022; 11:pathogens11091039. [PMID: 36145471 PMCID: PMC9501407 DOI: 10.3390/pathogens11091039] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/06/2022] [Accepted: 09/09/2022] [Indexed: 11/17/2022] Open
Abstract
Virus evolution is the change in the genetic structure of a viral population over time and results in the emergence of new viral variants, strains, and species with novel biological properties, including adaptation to new hosts. There are host, vector, environmental, and viral factors that contribute to virus evolution. To achieve or fine tune compatibility and successfully establish infection, viruses adapt to a particular host species or to a group of species. However, some viruses are better able to adapt to diverse hosts, vectors, and environments. Viruses generate genetic diversity through mutation, reassortment, and recombination. Plant viruses are exposed to genetic drift and selection pressures by host and vector factors, and random variants or those with a competitive advantage are fixed in the population and mediate the emergence of new viral strains or species with novel biological properties. This process creates a footprint in the virus genome evident as the preferential accumulation of substitutions, insertions, or deletions in areas of the genome that function as determinants of host adaptation. Here, with respect to plant viruses, we review the current understanding of the sources of variation, the effect of selection, and its role in virus evolution and host adaptation.
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9
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Li F, Ge L, Lozano-Durán R, Zhou X. Antiviral RNAi drives host adaptation to viral infection. Trends Microbiol 2022; 30:915-917. [PMID: 35931622 DOI: 10.1016/j.tim.2022.07.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 11/28/2022]
Abstract
Despite extensive understanding of antiviral RNAi in plants, whether and how natural variation in components of RNAi contributes to antiviral immunity remains obscure. Liu et al. recently identified novel positive and negative antiviral RNAi regulators, supporting RNAi's principal role in the dynamic virus-host coevolution in natural ecosystems.
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Affiliation(s)
- Fangfang Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Linhao Ge
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Rosa Lozano-Durán
- Department of Plant Biochemistry, Centre for Plant Molecular Biology (ZMBP), Eberhard Karls University, D-72076 Tübingen, Germany
| | - Xueping Zhou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
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10
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Liu S, Chen M, Li R, Li WX, Gal-On A, Jia Z, Ding SW. Identification of positive and negative regulators of antiviral RNA interference in Arabidopsis thaliana. Nat Commun 2022; 13:2994. [PMID: 35637208 PMCID: PMC9151786 DOI: 10.1038/s41467-022-30771-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 05/18/2022] [Indexed: 02/06/2023] Open
Abstract
Virus-host coevolution often drives virus immune escape. However, it remains unknown whether natural variations of plant virus resistance are enriched in genes of RNA interference (RNAi) pathway known to confer essential antiviral defense in plants. Here, we report two genome-wide association study screens to interrogate natural variation among wild-collected Arabidopsis thaliana accessions in quantitative resistance to the endemic cucumber mosaic virus (CMV). We demonstrate that the highest-ranked gene significantly associated with resistance from both screens acts to regulate antiviral RNAi in ecotype Columbia-0. One gene, corresponding to Reduced Dormancy 5 (RDO5), enhances resistance by promoting amplification of the virus-derived small interfering RNAs (vsiRNAs). Interestingly, the second gene, designated Antiviral RNAi Regulator 1 (VIR1), dampens antiviral RNAi so its genetic inactivation by CRISPR/Cas9 editing enhances both vsiRNA production and CMV resistance. Our findings identify positive and negative regulators of the antiviral RNAi defense that may play important roles in virus-host coevolution.
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Affiliation(s)
- Si Liu
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA, USA
| | - Meijuan Chen
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA, USA
| | - Ruidong Li
- Department of Botany & Plant Sciences, University of California, Riverside, CA, USA
| | - Wan-Xiang Li
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA, USA
| | - Amit Gal-On
- Department of Plant Pathology and Weed Science, Volcani Center, Rishon LeZion, 7528809, Israel
| | - Zhenyu Jia
- Department of Botany & Plant Sciences, University of California, Riverside, CA, USA.
| | - Shou-Wei Ding
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA, USA.
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Verchot J. Potato virus X: A global potato-infecting virus and type member of the Potexvirus genus. MOLECULAR PLANT PATHOLOGY 2022; 23:315-320. [PMID: 34791766 PMCID: PMC8828454 DOI: 10.1111/mpp.13163] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 05/24/2023]
Abstract
TAXONOMY Potato virus X is the type-member of the plant-infecting Potexvirus genus in the family Alphaflexiviridae. PHYSICAL PROPERTIES Potato virus X (PVX) virions are flexuous filaments 460-480 nm in length. Virions are 13 nm in diameter and have a helical pitch of 3.4 nm. The genome is approximately 6.4 kb with a 5' cap and 3' poly(A) terminus. PVX contains five open reading frames, four of which are essential for cell-to-cell and systemic movement. One protein encodes the viral replicase. Cellular inclusions, known as X-bodies, occur near the nucleus of virus-infected cells. HOSTS The primary host is potato, but it infects a wide range of dicots. Diagnostic hosts include Datura stramonium and Nicotiana tabacum. PVX is transmitted in nature by mechanical contact. USEFUL WEBSITE: https://talk.ictvonline.org/ictv-reports/ictv_online_report/positive-sense-rna-viruses/w/alphaflexiviridae/1330/genus-potexvirus.
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Affiliation(s)
- Jeanmarie Verchot
- Department of Plant Pathology & MicrobiologyTexas A&M UniversityCollege StationTXUSA
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12
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Jin L, Chen M, Xiang M, Guo Z. RNAi-Based Antiviral Innate Immunity in Plants. Viruses 2022; 14:v14020432. [PMID: 35216025 PMCID: PMC8875485 DOI: 10.3390/v14020432] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 12/13/2022] Open
Abstract
Multiple antiviral immunities were developed to defend against viral infection in hosts. RNA interference (RNAi)-based antiviral innate immunity is evolutionarily conserved in eukaryotes and plays a vital role against all types of viruses. During the arms race between the host and virus, many viruses evolve viral suppressors of RNA silencing (VSRs) to inhibit antiviral innate immunity. Here, we reviewed the mechanism at different stages in RNAi-based antiviral innate immunity in plants and the counteractions of various VSRs, mainly upon infection of RNA viruses in model plant Arabidopsis. Some critical challenges in the field were also proposed, and we think that further elucidating conserved antiviral innate immunity may convey a broad spectrum of antiviral strategies to prevent viral diseases in the future.
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13
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LaTourrette K, Holste NM, Garcia-Ruiz H. Polerovirus genomic variation. Virus Evol 2021; 7:veab102. [PMID: 35299789 PMCID: PMC8923251 DOI: 10.1093/ve/veab102] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 11/21/2021] [Accepted: 12/03/2021] [Indexed: 01/01/2023] Open
Abstract
Abstract
The polerovirus (family Solemoviridae, genus Polerovirus) genome consists of single-, positive-strand RNA organized in overlapping open reading frames (ORFs) that, in addition to others, code for protein 0 (P0, a gene silencing suppressor), a coat protein (CP, ORF3), and a read-through domain (ORF5) that is fused to the CP to form a CP-read-through (RT) protein. The genus Polerovirus contains twenty-six virus species that infect a wide variety of plants from cereals to cucurbits, to peppers. Poleroviruses are transmitted by a wide range of aphid species in the genera Rhopalosiphum, Stiobion, Aphis, and Myzus. Aphid transmission is mediated both by the CP and by the CP-RT. In viruses, mutational robustness and structural flexibility are necessary for maintaining functionality in genetically diverse sets of host plants and vectors. Under this scenario, within a virus genome, mutations preferentially accumulate in areas that are determinants of host adaptation or vector transmission. In this study, we profiled genomic variation in poleroviruses. Consistent with their multifunctional nature, single-nucleotide variation and selection analyses showed that ORFs coding for P0 and the read-through domain within the CP-RT are the most variable and contain the highest frequency of sites under positive selection. An order/disorder analysis showed that protein P0 is not disordered. In contrast, proteins CP-RT and virus protein genome-linked (VPg) contain areas of disorder. Disorder is a property of multifunctional proteins with multiple interaction partners. The results described here suggest that using contrasting mechanisms, P0, VPg, and CP-RT mediate adaptation to host plants and to vectors and are contributors to the broad host and vector range of poleroviruses. Profiling genetic variation across the polerovirus genome has practical applications in diagnostics, breeding for resistance, and identification of susceptibility genes and contributes to our understanding of virus interactions with their host, vectors, and environment.
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Affiliation(s)
- Katherine LaTourrette
- Nebraska Center for Virology, University of Nebraska-Lincoln, 4240 Fair Street, Lincoln, NE 68583, USA
- Department of Plant Pathology, University of Nebraska-Lincoln, 406 Plant Science Hall, Lincoln, NE 68583, USA
- Complex Biosystems Interdisciplinary Life Sciences Program, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln, 2200 Vine Street, Lincoln, NE 68583, USA
| | - Natalie M Holste
- Nebraska Center for Virology, University of Nebraska-Lincoln, 4240 Fair Street, Lincoln, NE 68583, USA
- Department of Plant Pathology, University of Nebraska-Lincoln, 406 Plant Science Hall, Lincoln, NE 68583, USA
| | - Hernan Garcia-Ruiz
- Nebraska Center for Virology, University of Nebraska-Lincoln, 4240 Fair Street, Lincoln, NE 68583, USA
- Department of Plant Pathology, University of Nebraska-Lincoln, 406 Plant Science Hall, Lincoln, NE 68583, USA
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Wang Z, Chen D, Sun F, Guo W, Wang W, Li X, Lan Y, Du L, Li S, Fan Y, Zhou Y, Zhao H, Zhou T. ARGONAUTE 2 increases rice susceptibility to rice black-streaked dwarf virus infection by epigenetically regulating HEXOKINASE 1 expression. MOLECULAR PLANT PATHOLOGY 2021; 22:1029-1040. [PMID: 34110094 PMCID: PMC8359002 DOI: 10.1111/mpp.13091] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/20/2021] [Accepted: 05/13/2021] [Indexed: 05/08/2023]
Abstract
ARGONAUTE (AGO) proteins play crucial roles in plant defence against virus invasion. To date, the role of OsAGO2 in rice antiviral defence remains largely unknown. In this study, we determined that the expression of OsAGO2 in rice was induced upon rice black-streaked dwarf virus (RBSDV) infection. Using transgenic rice plants overexpressing OsAGO2 and Osago2 mutants generated through transposon-insertion or CRISPR/Cas9 technology, we found that overexpression of OsAGO2 enhanced rice susceptibility to RBSDV infection. Osago2 mutant lines exhibited strong resistance to RBSDV infection through the elicitation of an early defence response, including reprogramming defence gene expression and production of reactive oxygen species (ROS). Compared to Nipponbare control, the expression level of OsHXK1 (HEXOKINASE 1) increased significantly, and the methylation levels of its promoter decreased in the Osago2 mutant on RBSDV infection. The expression profile of OsHXK1 was the opposite to that of OsAGO2 during RBSDV infection. Overexpression of OsHXK1 in rice also induced ROS production and enhanced rice resistance to RBSDV infection. These results indicate that OsHXK1 controls ROS accumulation and is regulated by OsAGO2 through epigenetic regulation. It is noteworthy that the Osago2 mutant plants are also resistant to southern rice black-streaked dwarf virus infection, another member of the genus Fijivirus. Based on the results presented in this paper, we conclude that OsAGO2 modulates rice susceptibility to fijivirus infection by suppressing OsHXK1 expression, leading to the onset of ROS-mediated resistance. This discovery may benefit future rice breeding programmes for virus resistance.
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Affiliation(s)
- Zhaoyun Wang
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
| | - Dongyue Chen
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityNanjing, Jiangsu ProvinceChina
| | - Feng Sun
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
| | - Wei Guo
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
- Key Laboratory of Agricultural Biodiversity and Disease Control of Ministry of EducationCollege of Plant ProtectionYunnan Agricultural UniversityKunming, Yunnan ProvinceChina
| | - Wei Wang
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityNanjing, Jiangsu ProvinceChina
| | - Xuejuan Li
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
| | - Ying Lan
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
| | - Linlin Du
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
| | - Shuo Li
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
| | - Yongjian Fan
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
| | - Yijun Zhou
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
| | - Hongwei Zhao
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityNanjing, Jiangsu ProvinceChina
| | - Tong Zhou
- Key Laboratory of Food Quality and SafetyInstitute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjing, Jiangsu ProvinceChina
- International Rice Research Institute and Jiangsu Academy of Agricultural Sciences Joint LaboratoryNanjing, Jiangsu ProvinceChina
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15
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Ross BT, Zidack NK, Flenniken ML. Extreme Resistance to Viruses in Potato and Soybean. FRONTIERS IN PLANT SCIENCE 2021; 12:658981. [PMID: 33889169 PMCID: PMC8056081 DOI: 10.3389/fpls.2021.658981] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/12/2021] [Indexed: 05/31/2023]
Abstract
Plant pathogens, including viruses, negatively impact global crop production. Plants have evolved complex immune responses to pathogens. These responses are often controlled by nucleotide-binding leucine-rich repeat proteins (NLRs), which recognize intracellular, pathogen-derived proteins. Genetic resistance to plant viruses is often phenotypically characterized by programmed cell death at or near the infection site; a reaction termed the hypersensitive response. Although visualization of the hypersensitive response is often used as a hallmark of resistance, the molecular mechanisms leading to the hypersensitive response and associated cell death vary. Plants with extreme resistance to viruses rarely exhibit symptoms and have little to no detectable virus replication or spread beyond the infection site. Both extreme resistance and the hypersensitive response can be activated by the same NLR genes. In many cases, genes that normally provide an extreme resistance phenotype can be stimulated to cause a hypersensitive response by experimentally increasing cellular levels of pathogen-derived elicitor protein(s). The molecular mechanisms of extreme resistance and its relationship to the hypersensitive response are largely uncharacterized. Studies on potato and soybean cultivars that are resistant to strains of Potato virus Y (PVY), Potato virus X (PVX), and Soybean mosaic virus (SMV) indicate that abscisic acid (ABA)-mediated signaling and NLR nuclear translocation are important for the extreme resistance response. Recent research also indicates that some of the same proteins are involved in both extreme resistance and the hypersensitive response. Herein, we review and synthesize published studies on extreme resistance in potato and soybean, and describe studies in additional species, including model plant species, to highlight future research avenues that may bridge the gaps in our knowledge of plant antiviral defense mechanisms.
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Affiliation(s)
- Brian T. Ross
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, United States
| | - Nina K. Zidack
- Montana State Seed Potato Certification Lab, Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, United States
| | - Michelle L. Flenniken
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, United States
- Montana State Seed Potato Certification Lab, Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, United States
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16
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He G, Qin L, Tian W, Meng L, He T, Zhao D. Heavy Metal Transporters-Associated Proteins in S. tuberosum: Genome-Wide Identification, Comprehensive Gene Feature, Evolution and Expression Analysis. Genes (Basel) 2020; 11:genes11111269. [PMID: 33126505 PMCID: PMC7694169 DOI: 10.3390/genes11111269] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/20/2020] [Accepted: 10/25/2020] [Indexed: 02/07/2023] Open
Abstract
Plants have evolved a number of defense and adaptation responses to protect themselves against challenging environmental stresses. Genes containing a heavy metal associated (HMA) domain are required for the spatiotemporal transportation of metal ions that bind with various enzymes and co-factors within the cell. To uncover the underlying mechanisms mediated by StHMA genes, we identified 36 gene members in the StHMA family and divided them into six subfamilies by phylogenetic analysis. The StHMAs had high collinearity and were segmentally duplicated. Structurally, most StHMAs had one HMA domain, StHIPPc and StRNA1 subfamilies had two, and 13 StHMAs may be genetically variable. The StHMA gene structures and motifs varied considerably among the various classifications, this suggests the StHMA family is diverse in genetic functions. The promoter analysis showed that the StHMAs had six main cis-acting elements with abiotic stress. An expression pattern analysis revealed that the StHMAs were expressed tissue specifically, and a variety of abiotic stresses may induce the expression of StHMA family genes. The HMA transporter family may be regulated and expressed by a series of complex signal networks under abiotic stress. The results of this study may help to establish a theoretical foundation for further research investigating the functions of HMA genes in Solanum tuberosum to elucidate their regulatory role in the mechanism governing the response of plants to abiotic stress.
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Affiliation(s)
- Guandi He
- The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Institute of Agro-Bioengineering and College of Life Sciences, Guizhou University, Guiyang 550025, China; (G.H.); (L.Q.)
| | - Lijun Qin
- The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Institute of Agro-Bioengineering and College of Life Sciences, Guizhou University, Guiyang 550025, China; (G.H.); (L.Q.)
| | - Weijun Tian
- Agricultural College, Guizhou University, Guiyang 550025, China; (W.T.); (L.M.)
| | - Lulu Meng
- Agricultural College, Guizhou University, Guiyang 550025, China; (W.T.); (L.M.)
| | - Tengbing He
- Agricultural College, Guizhou University, Guiyang 550025, China; (W.T.); (L.M.)
- Institute of New Rural Development of Guizhou University, Guiyang 550025, China
- Correspondence: (T.H.); (D.Z.)
| | - Degang Zhao
- The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Institute of Agro-Bioengineering and College of Life Sciences, Guizhou University, Guiyang 550025, China; (G.H.); (L.Q.)
- Guizhou Academy of Agricultural Science, Guiyang 550025, China
- Correspondence: (T.H.); (D.Z.)
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17
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Silva-Martins G, Bolaji A, Moffett P. What does it take to be antiviral? An Argonaute-centered perspective on plant antiviral defense. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6197-6210. [PMID: 32835379 DOI: 10.1093/jxb/eraa377] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 08/12/2020] [Indexed: 06/11/2023]
Abstract
RNA silencing is a major mechanism of constitutive antiviral defense in plants, mediated by a number of proteins, including the Dicer-like (DCL) and Argonaute (AGO) endoribonucleases. Both DCL and AGO protein families comprise multiple members. In particular, the AGO protein family has expanded considerably in different plant lineages, with different family members having specialized functions. Although the general mode of action of AGO proteins is well established, the properties that make different AGO proteins more or less efficient at targeting viruses are less well understood. In this report, we review methodologies used to study AGO antiviral activity and current knowledge about which AGO family members are involved in antiviral defense. In addition, we discuss what is known about the different properties of AGO proteins thought to be associated with this function.
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Affiliation(s)
| | - Ayooluwa Bolaji
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Peter Moffett
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
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18
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Incarbone M, Scheer H, Hily JM, Kuhn L, Erhardt M, Dunoyer P, Altenbach D, Ritzenthaler C. Characterization of a DCL2-Insensitive Tomato Bushy Stunt Virus Isolate Infecting Arabidopsis thaliana. Viruses 2020; 12:E1121. [PMID: 33023227 PMCID: PMC7650723 DOI: 10.3390/v12101121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 12/17/2022] Open
Abstract
Tomato bushy stunt virus (TBSV), the type member of the genus Tombusvirus in the family Tombusviridae is one of the best studied plant viruses. The TBSV natural and experimental host range covers a wide spectrum of plants including agricultural crops, ornamentals, vegetables and Nicotiana benthamiana. However, Arabidopsis thaliana, the well-established model organism in plant biology, genetics and plant-microbe interactions is absent from the list of known TBSV host plant species. Most of our recent knowledge of the virus life cycle has emanated from studies in Saccharomyces cerevisiae, a surrogate host for TBSV that lacks crucial plant antiviral mechanisms such as RNA interference (RNAi). Here, we identified and characterized a TBSV isolate able to infect Arabidopsis with high efficiency. We demonstrated by confocal and 3D electron microscopy that in Arabidopsis TBSV-BS3Ng replicates in association with clustered peroxisomes in which numerous spherules are induced. A dsRNA-centered immunoprecipitation analysis allowed the identification of TBSV-associated host components including DRB2 and DRB4, which perfectly localized to replication sites, and NFD2 that accumulated in larger viral factories in which peroxisomes cluster. By challenging knock-out mutants for key RNAi factors, we showed that TBSV-BS3Ng undergoes a non-canonical RNAi defensive reaction. In fact, unlike other RNA viruses described, no 22nt TBSV-derived small RNA are detected in the absence of DCL4, indicating that this virus is DCL2-insensitive. The new Arabidopsis-TBSV-BS3Ng pathosystem should provide a valuable new model for dissecting plant-virus interactions in complement to Saccharomyces cerevisiae.
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Affiliation(s)
- Marco Incarbone
- Institut de Biologie de Moléculaire des Plantes, CNRS, Université de Strasbourg, 67000 Strasbourg, France; (H.S.); (M.E.); (P.D.)
| | - Hélene Scheer
- Institut de Biologie de Moléculaire des Plantes, CNRS, Université de Strasbourg, 67000 Strasbourg, France; (H.S.); (M.E.); (P.D.)
| | - Jean-Michel Hily
- IFV, Le Grau-Du-Roi, Université de Strasbourg, INRAE, SVQV UNR-A 1131, 68000 Colmar, France;
| | - Lauriane Kuhn
- Plateforme protéomique Strasbourg Esplanade FR1589 du CNRS, Université de Strasbourg, 67000 Strasbourg, France;
| | - Mathieu Erhardt
- Institut de Biologie de Moléculaire des Plantes, CNRS, Université de Strasbourg, 67000 Strasbourg, France; (H.S.); (M.E.); (P.D.)
| | - Patrice Dunoyer
- Institut de Biologie de Moléculaire des Plantes, CNRS, Université de Strasbourg, 67000 Strasbourg, France; (H.S.); (M.E.); (P.D.)
| | - Denise Altenbach
- Bioreba AG, Christoph Merian Ring 7, CH-4153 Reinach, Switzerland;
| | - Christophe Ritzenthaler
- Institut de Biologie de Moléculaire des Plantes, CNRS, Université de Strasbourg, 67000 Strasbourg, France; (H.S.); (M.E.); (P.D.)
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