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Liu S, Ding SW. Antiviral RNA interference inhibits virus vertical transmission in plants. Cell Host Microbe 2024; 32:1691-1704.e4. [PMID: 39243759 DOI: 10.1016/j.chom.2024.08.009] [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: 06/11/2024] [Revised: 07/14/2024] [Accepted: 08/12/2024] [Indexed: 09/09/2024]
Abstract
Known for over a century, seed transmission of plant viruses promotes trans-continental virus dissemination and provides the source of infection to trigger devastating disease epidemics in crops. However, it remains unknown whether there is a genetically defined immune pathway to suppress virus vertical transmission in plants. Here, we demonstrate potent immunosuppression of cucumber mosaic virus (CMV) seed transmission in its natural host Arabidopsis thaliana by antiviral RNA interference (RNAi) pathway. Immunofluorescence microscopy reveals predominant embryo infection at four stages of embryo development. We show that antiviral RNAi confers resistance to seed infection with different genetic requirements and drastically enhanced potency compared with the inhibition of systemic infection of whole plants. Moreover, we detect efficient seed transmission of a mutant CMV lacking its RNAi suppressor gene in mutant plants defective in antiviral RNAi, providing further support for the immunosuppression of seed transmission by antiviral RNAi.
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Affiliation(s)
- Si Liu
- Department of Microbiology & Plant Pathology and Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA
| | - Shou-Wei Ding
- Department of Microbiology & Plant Pathology and Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA.
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Hayashi S, Souvan JM, Bally J, de Felippes FF, Waterhouse PM. Exploring the source of TYLCV resistance in Nicotiana benthamiana. FRONTIERS IN PLANT SCIENCE 2024; 15:1404160. [PMID: 38863537 PMCID: PMC11165019 DOI: 10.3389/fpls.2024.1404160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 05/08/2024] [Indexed: 06/13/2024]
Abstract
Tomato Yellow Leaf Curl Virus (TYLCV) is one of the most devastating pathogens of tomato, worldwide. It is vectored by the globally prevalent whitefly, Bemisia tabaci, and is asymptomatic in a wide range of plant species that act as a virus reservoir. The most successful crop protection for tomato in the field has been from resistance genes, of which five loci have been introgressed fromwild relatives. Of these, the Ty-1/Ty-3 locus, which encodes an RNA-dependent RNA polymerase 3 (RDR3), has been the most effective. Nevertheless, several TYLCV strains that break this resistance are beginning to emerge, increasing the need for new sources of resistance. Here we use segregation analysis and CRISPR-mediated gene dysfunctionalisation to dissect the differential response of two isolates of Nicotiana benthamiana to TYLCV infection. Our study indicates the presence of a novel non-RDR3, but yet to be identified, TYLCV resistance gene in a wild accession of N. benthamiana. This gene has the potential to be incorporated into tomatoes.
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Affiliation(s)
- Satomi Hayashi
- Centre for Agriculture and the Bioeconomy, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, Queensland University of Technology, Brisbane, QLD, Australia
| | - Jacqueline M. Souvan
- Centre for Agriculture and the Bioeconomy, Queensland University of Technology, Brisbane, QLD, Australia
| | - Julia Bally
- Centre for Agriculture and the Bioeconomy, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, Queensland University of Technology, Brisbane, QLD, Australia
| | - Felipe F. de Felippes
- Centre for Agriculture and the Bioeconomy, Queensland University of Technology, Brisbane, QLD, Australia
| | - Peter M. Waterhouse
- Centre for Agriculture and the Bioeconomy, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, Queensland University of Technology, Brisbane, QLD, Australia
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Crawshaw S, Murphy AM, Rowling PJE, Nietlispach D, Itzhaki LS, Carr JP. Investigating the Interactions of the Cucumber Mosaic Virus 2b Protein with the Viral 1a Replicase Component and the Cellular RNA Silencing Factor Argonaute 1. Viruses 2024; 16:676. [PMID: 38793558 PMCID: PMC11125589 DOI: 10.3390/v16050676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 04/13/2024] [Accepted: 04/16/2024] [Indexed: 05/26/2024] Open
Abstract
The cucumber mosaic virus (CMV) 2b protein is a suppressor of plant defenses and a pathogenicity determinant. Amongst the 2b protein's host targets is the RNA silencing factor Argonaute 1 (AGO1), which it binds to and inhibits. In Arabidopsis thaliana, if 2b-induced inhibition of AGO1 is too efficient, it induces reinforcement of antiviral silencing by AGO2 and triggers increased resistance against aphids, CMV's insect vectors. These effects would be deleterious to CMV replication and transmission, respectively, but are moderated by the CMV 1a protein, which sequesters sufficient 2b protein molecules into P-bodies to prevent excessive inhibition of AGO1. Mutant 2b protein variants were generated, and red and green fluorescent protein fusions were used to investigate subcellular colocalization with AGO1 and the 1a protein. The effects of mutations on complex formation with the 1a protein and AGO1 were investigated using bimolecular fluorescence complementation and co-immunoprecipitation assays. Although we found that residues 56-60 influenced the 2b protein's interactions with the 1a protein and AGO1, it appears unlikely that any single residue or sequence domain is solely responsible. In silico predictions of intrinsic disorder within the 2b protein secondary structure were supported by circular dichroism (CD) but not by nuclear magnetic resonance (NMR) spectroscopy. Intrinsic disorder provides a plausible model to explain the 2b protein's ability to interact with AGO1, the 1a protein, and other factors. However, the reasons for the conflicting conclusions provided by CD and NMR must first be resolved.
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Affiliation(s)
- Sam Crawshaw
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (S.C.); (A.M.M.)
| | - Alex M. Murphy
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (S.C.); (A.M.M.)
| | - Pamela J. E. Rowling
- Department of Pharmacology, University of Cambridge, Tennis Court Rd., Cambridge CB2 1PD, UK; (P.J.E.R.); (L.S.I.)
| | - Daniel Nietlispach
- Department of Biochemistry, University of Cambridge, Sanger Building, 80 Tennis Court Rd., Cambridge CB2 1GA, UK;
| | - Laura S. Itzhaki
- Department of Pharmacology, University of Cambridge, Tennis Court Rd., Cambridge CB2 1PD, UK; (P.J.E.R.); (L.S.I.)
| | - John P. Carr
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (S.C.); (A.M.M.)
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Liu S, Han Y, Li WX, Ding SW. Infection Defects of RNA and DNA Viruses Induced by Antiviral RNA Interference. Microbiol Mol Biol Rev 2023; 87:e0003522. [PMID: 37052496 PMCID: PMC10304667 DOI: 10.1128/mmbr.00035-22] [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: 04/14/2023] Open
Abstract
Immune recognition of viral genome-derived double-stranded RNA (dsRNA) molecules and their subsequent processing into small interfering RNAs (siRNAs) in plants, invertebrates, and mammals trigger specific antiviral immunity known as antiviral RNA interference (RNAi). Immune sensing of viral dsRNA is sequence-independent, and most regions of viral RNAs are targeted by virus-derived siRNAs which extensively overlap in sequence. Thus, the high mutation rates of viruses do not drive immune escape from antiviral RNAi, in contrast to other mechanisms involving specific virus recognition by host immune proteins such as antibodies and resistance (R) proteins in mammals and plants, respectively. Instead, viruses actively suppress antiviral RNAi at various key steps with a group of proteins known as viral suppressors of RNAi (VSRs). Some VSRs are so effective in virus counter-defense that potent inhibition of virus infection by antiviral RNAi is undetectable unless the cognate VSR is rendered nonexpressing or nonfunctional. Since viral proteins are often multifunctional, resistance phenotypes of antiviral RNAi are accurately defined by those infection defects of VSR-deletion mutant viruses that are efficiently rescued by host deficiency in antiviral RNAi. Here, we review and discuss in vivo infection defects of VSR-deficient RNA and DNA viruses resulting from the actions of host antiviral RNAi in model systems.
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Affiliation(s)
- Si Liu
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, USA
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
| | - Yanhong Han
- Vector-borne Virus Research Center, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Wan-Xiang Li
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, USA
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
| | - Shou-Wei Ding
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, USA
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
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Akbarimotlagh M, Azizi A, Shams-Bakhsh M, Jafari M, Ghasemzadeh A, Palukaitis P. Critical points for the design and application of RNA silencing constructs for plant virus resistance. Adv Virus Res 2023; 115:159-203. [PMID: 37173065 DOI: 10.1016/bs.aivir.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Control of plant virus diseases is a big challenge in agriculture as is resistance in plant lines to infection by viruses. Recent progress using advanced technologies has provided fast and durable alternatives. One of the most promising techniques against plant viruses that is cost-effective and environmentally safe is RNA silencing or RNA interference (RNAi), a technology that could be used alone or along with other control methods. To achieve the goals of fast and durable resistance, the expressed and target RNAs have been examined in many studies, with regard to the variability in silencing efficiency, which is regulated by various factors such as target sequences, target accessibility, RNA secondary structures, sequence variation in matching positions, and other intrinsic characteristics of various small RNAs. Developing a comprehensive and applicable toolbox for the prediction and construction of RNAi helps researchers to achieve the acceptable performance level of silencing elements. Although the attainment of complete prediction of RNAi robustness is not possible, as it also depends on the cellular genetic background and the nature of the target sequences, some important critical points have been discerned. Thus, the efficiency and robustness of RNA silencing against viruses can be improved by considering the various parameters of the target sequence and the construct design. In this review, we provide a comprehensive treatise regarding past, present and future prospective developments toward designing and applying RNAi constructs for resistance to plant viruses.
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Affiliation(s)
- Masoud Akbarimotlagh
- Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University (TMU), Tehran, Iran
| | - Abdolbaset Azizi
- Department of Plant Protection, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran.
| | - Masoud Shams-Bakhsh
- Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University (TMU), Tehran, Iran
| | - Majid Jafari
- Department of Plant Protection, Higher Education Complex of Saravan, Saravan, Iran
| | - Aysan Ghasemzadeh
- Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University (TMU), Tehran, Iran
| | - Peter Palukaitis
- Department of Horticulture Sciences, Seoul Women's University, Seoul, Republic of Korea.
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Gong Q, Wang Y, Jin Z, Hong Y, Liu Y. Transcriptional and post-transcriptional regulation of RNAi-related gene expression during plant-virus interactions. STRESS BIOLOGY 2022; 2:33. [PMID: 37676459 PMCID: PMC10441928 DOI: 10.1007/s44154-022-00057-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 08/14/2022] [Indexed: 09/08/2023]
Abstract
As sessile organisms, plants encounter diverse invasions from pathogens including viruses. To survive and thrive, plants have evolved multilayered defense mechanisms to combat virus infection. RNAi, also known as RNA silencing, is an across-kingdom innate immunity and gene regulatory machinery. Molecular framework and crucial roles of RNAi in antiviral defense have been well-characterized. However, it is largely unknown that how RNAi is transcriptionally regulated to initiate, maintain and enhance cellular silencing under normal or stress conditions. Recently, insights into the transcriptional and post-transcriptional regulation of RNAi-related genes in different physiological processes have been emerging. In this review, we integrate these new findings to provide updated views on how plants modulate RNAi machinery at the (post-) transcriptional level to respond to virus infection.
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Affiliation(s)
- Qian Gong
- MOE Key Laboratory of Bioinformatics and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China
| | - Yunjing Wang
- MOE Key Laboratory of Bioinformatics and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China
| | - Zhenhui Jin
- Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
- School of Science and the Environment, University of Worcester, Worcester, WR2 6AJ, UK
| | - Yiguo Hong
- Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
- School of Science and the Environment, University of Worcester, Worcester, WR2 6AJ, UK
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Yule Liu
- MOE Key Laboratory of Bioinformatics and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China.
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Rattan UK, Kumar S, Kumari R, Bharti M, Hallan V. Homeobox 27, a Homeodomain Transcription Factor, Confers Tolerances to CMV by Associating with Cucumber Mosaic Virus 2b Protein. Pathogens 2022; 11:pathogens11070788. [PMID: 35890032 PMCID: PMC9323240 DOI: 10.3390/pathogens11070788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/06/2022] [Accepted: 07/06/2022] [Indexed: 11/16/2022] Open
Abstract
Transcription factors (TFs) play an important role in plant development; however, their role during viral infection largely remains unknown. The present study was designed to uncover the role transcription factors play in Cucumber mosaic virus (CMV) infection. During the screening of an Arabidopsis thaliana (Col-0) transcription factor library, using the CMV 2b protein as bait in the yeast two-hybrid system, the 2b protein interacted with Homeobox protein 27 (HB27). HB27 belongs to the zinc finger homeodomain family and is known to have a regulatory role in flower development, and responses to biotic and abiotic stress. The interaction between CMV 2b and HB27 proteins was further validated using in planta (bimolecular fluorescence complementation assay) and in vitro far-Western blotting (FWB) methods. In the bimolecular fluorescence complementation assay, these proteins reconstituted YFP fluorescence in the nucleus and the cytoplasmic region as small fluorescent dots. In FWB, positive interaction was detected using bait anti-MYC antibody on the target HB27-HA protein. During CMV infection, upregulation (~3-fold) of the HB27 transcript was observed at 14 days post-infection (dpi) in A. thaliana plants, and expression declined to the same as healthy plants at 21 dpi. To understand the role of the HB27 protein during CMV infection, virus accumulation was determined in HB27-overexpressing (HB27 OE) and knockout mutants. In HB27-overexpressing lines, infected plants developed mild symptoms, accumulating a lower virus titer at 21 dpi compared to wild-type plants. Additionally, knockout HB27 mutants had more severe symptoms and a higher viral accumulation than wild-type plants. These results indicate that HB27 plays an important role in the regulation of plant defense against plant virus infection.
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Affiliation(s)
- Usha Kumari Rattan
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Surender Kumar
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
| | - Reenu Kumari
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
- College of Horticulture and Forestry, Dr. Y. S. Parmar University of Horticulture and Forestry, Thunag, Mandi 175048, India
| | - Monika Bharti
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
| | - Vipin Hallan
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Correspondence: ; Tel.: +91-1894-233338; Fax: +91-1894-230433
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Leibman D, Pashkovsky E, Shnaider Y, Shtarkman M, Gaba V, Gal-On A. Analysis of the RNA-Dependent RNA Polymerase 1 (RDR1) Gene Family in Melon. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11141795. [PMID: 35890429 PMCID: PMC9320487 DOI: 10.3390/plants11141795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/16/2022] [Accepted: 06/28/2022] [Indexed: 05/14/2023]
Abstract
RNA-dependent RNA polymerase 1 (RDR1) plays a crucial defense role against plant viruses by secondary amplification of viral double-stranded RNA in the gene-silencing pathway. In this study, it was found that melon (Cucumis melo) encodes four RDR1 genes (CmRDR1a, b, c1 and c2) similar to the CsRDR1 gene family of cucumber (C. sativus). However, in contrast to cucumber, melon harbors a truncated CmRDR1b gene. In healthy plants, CmRDR1a was expressed, whereas the expression of CmRDR1c1/c2 was not detected. CmRDR1a expression level increased 20-fold upon cucumber mosaic virus (CMV) infection and was not increased in melon plants infected with zucchini yellow mosaic virus (ZYMV), cucumber vein yellowing virus (CVYV) and cucumber green mottle mosaic virus (CGMMV). The expression of CmRDR1c1/c2 genes was induced differentially by infection with viruses from different families: high levels of ~340-, 172- and 115-fold increases were induced by CMV, CVYV and CGMMV, respectively, and relatively low-level increases by potyvirus infection (4- to 6-fold). CMV mutants lacking the viral silencing suppressor 2b protein did not cause increased CmRDR1c/c2 expression; knockout of CmRDR1c1/c2 by CRISPR/Cas9 increased susceptibility to CMV but not to ZYMV. Therefore, it is suggested that the sensitivity of melon to viruses from different families is a result of the loss of function of CmRDR1b.
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