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Palukaitis P, Yoon JY. Defense signaling pathways in resistance to plant viruses: Crosstalk and finger pointing. Adv Virus Res 2024; 118:77-212. [PMID: 38461031 DOI: 10.1016/bs.aivir.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2024]
Abstract
Resistance to infection by plant viruses involves proteins encoded by plant resistance (R) genes, viz., nucleotide-binding leucine-rich repeats (NLRs), immune receptors. These sensor NLRs are activated either directly or indirectly by viral protein effectors, in effector-triggered immunity, leading to induction of defense signaling pathways, resulting in the synthesis of numerous downstream plant effector molecules that inhibit different stages of the infection cycle, as well as the induction of cell death responses mediated by helper NLRs. Early events in this process involve recognition of the activation of the R gene response by various chaperones and the transport of these complexes to the sites of subsequent events. These events include activation of several kinase cascade pathways, and the syntheses of two master transcriptional regulators, EDS1 and NPR1, as well as the phytohormones salicylic acid, jasmonic acid, and ethylene. The phytohormones, which transit from a primed, resting states to active states, regulate the remainder of the defense signaling pathways, both directly and by crosstalk with each other. This regulation results in the turnover of various suppressors of downstream events and the synthesis of various transcription factors that cooperate and/or compete to induce or suppress transcription of either other regulatory proteins, or plant effector molecules. This network of interactions results in the production of defense effectors acting alone or together with cell death in the infected region, with or without the further activation of non-specific, long-distance resistance. Here, we review the current state of knowledge regarding these processes and the components of the local responses, their interactions, regulation, and crosstalk.
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Affiliation(s)
- Peter Palukaitis
- Graduate School of Plant Protection and Quarantine, Jeonbuk National University, Jeonju, Jeollabuk-do, Republic of Korea.
| | - Ju-Yeon Yoon
- Graduate School of Plant Protection and Quarantine, Jeonbuk National University, Jeonju, Jeollabuk-do, Republic of Korea.
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2
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Incarbone M, Bradamante G, Pruckner F, Wegscheider T, Rozhon W, Nguyen V, Gutzat R, Mérai Z, Lendl T, MacFarlane S, Nodine M, Scheid OM. Salicylic acid and RNA interference mediate antiviral immunity of plant stem cells. Proc Natl Acad Sci U S A 2023; 120:e2302069120. [PMID: 37824524 PMCID: PMC10589665 DOI: 10.1073/pnas.2302069120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 08/30/2023] [Indexed: 10/14/2023] Open
Abstract
Stem cells are essential for the development and organ regeneration of multicellular organisms, so their infection by pathogenic viruses must be prevented. Accordingly, mammalian stem cells are highly resistant to viral infection due to dedicated antiviral pathways including RNA interference (RNAi). In plants, a small group of stem cells harbored within the shoot apical meristem generate all postembryonic above-ground tissues, including the germline cells. Many viruses do not proliferate in these cells, yet the molecular bases of this exclusion remain only partially understood. Here, we show that a plant-encoded RNA-dependent RNA polymerase, after activation by the plant hormone salicylic acid, amplifies antiviral RNAi in infected tissues. This provides stem cells with RNA-based virus sequence information, which prevents virus proliferation. Furthermore, we find RNAi to be necessary for stem cell exclusion of several unrelated RNA viruses, despite their ability to efficiently suppress RNAi in the rest of the plant. This work elucidates a molecular pathway of great biological and economic relevance and lays the foundations for our future understanding of the unique systems underlying stem cell immunity.
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Affiliation(s)
- Marco Incarbone
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter, Vienna1030, Austria
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, Potsdam14476, Germany
| | - Gabriele Bradamante
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter, Vienna1030, Austria
| | - Florian Pruckner
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter, Vienna1030, Austria
| | - Tobias Wegscheider
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter, Vienna1030, Austria
| | - Wilfried Rozhon
- Department of Agriculture, Ecotrophology, and Landscape Development, Anhalt University of Applied Sciences, Bernburg06406, Germany
| | - Vu Nguyen
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter, Vienna1030, Austria
| | - Ruben Gutzat
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter, Vienna1030, Austria
| | - Zsuzsanna Mérai
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter, Vienna1030, Austria
| | - Thomas Lendl
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna1030, Austria
| | - Stuart MacFarlane
- The James Hutton Institute, Invergowrie, ScotlandDD25DA, United Kingdom
| | - Michael Nodine
- Department of Plant Sciences, Laboratory of Molecular Biology, Wageningen University and Research, Wageningen6700 AP, The Netherlands
| | - Ortrun Mittelsten Scheid
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter, Vienna1030, Austria
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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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Carr JP, Murphy AM, Tungadi T, Yoon JY. Plant defense signals: Players and pawns in plant-virus-vector interactions. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 279:87-95. [PMID: 30709497 DOI: 10.1016/j.plantsci.2018.04.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/07/2018] [Accepted: 04/13/2018] [Indexed: 06/09/2023]
Abstract
Plant viruses face an array of host defenses. Well-studied responses that protect against viruses include effector-triggered immunity, induced resistance (such as systemic acquired resistance mediated by salicylic acid), and RNA silencing. Recent work shows that viruses are also affected by non-host resistance mechanisms; previously thought to affect only bacteria, oomycetes and fungi. However, an enduring puzzle is how viruses are inhibited by several inducible host resistance mechanisms. Many viruses have been shown to encode factors that inhibit antiviral silencing. A number of these, including the cucumoviral 2b protein, the poytviral P1/HC-Pro and, respectively, geminivirus or satellite DNA-encoded proteins such as the C2 or βC1, also inhibit defensive signaling mediated by salicylic acid and jasmonic acid. This helps to explain how viruses can, in some cases, overcome host resistance. Additionally, interference with defensive signaling provides a means for viruses to manipulate plant-insect interactions. This is important because insects, particularly aphids and whiteflies, transmit many viruses. Indeed, there is now substantial evidence that viruses can enhance their own transmission through their effects on hosts. Even more surprisingly, it appears that viruses may be able to manipulate plant interactions with beneficial insects by, for example, 'paying back' their hosts by attracting pollinators.
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Affiliation(s)
- John P Carr
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom.
| | - Alex M Murphy
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom
| | - Trisna Tungadi
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom
| | - Ju-Yeon Yoon
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom; Virology Unit, Department of Horticultural and Herbal Environment, National Institute of Horticultural and Herbal Science, Rural Development Agency, Wanju, 55365, Republic of Korea
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5
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Leibman D, Kravchik M, Wolf D, Haviv S, Weissberg M, Ophir R, Paris HS, Palukaitis P, Ding S, Gaba V, Gal‐On A. Differential expression of cucumber RNA-dependent RNA polymerase 1 genes during antiviral defence and resistance. MOLECULAR PLANT PATHOLOGY 2018; 19:300-312. [PMID: 27879040 PMCID: PMC6637986 DOI: 10.1111/mpp.12518] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 11/20/2016] [Accepted: 11/20/2016] [Indexed: 05/21/2023]
Abstract
RNA-dependent RNA polymerase 1 (RDR1) plays a crucial role in plant defence against viruses. In this study, it was observed that cucumber, Cucumis sativus, uniquely encodes a small gene family of four RDR1 genes. The cucumber RDR1 genes (CsRDR1a, CsRDR1b and duplicated CsRDR1c1/c2) shared 55%-60% homology in their encoded amino acid sequences. In healthy cucumber plants, RDR1a and RDR1b transcripts were expressed at higher levels than transcripts of RDR1c1/c2, which were barely detectable. The expression of all four CsRDR1 genes was induced by virus infection, after which the expression level of CsRDR1b increased 10-20-fold in several virus-resistant cucumber cultivars and in a broad virus-resistant transgenic cucumber line expressing a high level of transgene small RNAs, all without alteration in salicylic acid (SA) levels. By comparison, CsRDR1c1/c2 genes were highly induced (25-1300-fold) in susceptible cucumber cultivars infected with RNA or DNA viruses. Inhibition of RDR1c1/c2 expression led to increased virus accumulation. Ectopic application of SA induced the expression of cucumber RDR1a, RDR1b and RDRc1/c2 genes. A constitutive high level of RDR1b gene expression independent of SA was found to be associated with broad virus resistance. These findings show that multiple RDR1 genes are involved in virus resistance in cucumber and are regulated in a coordinated fashion with different expression profiles.
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Affiliation(s)
- Diana Leibman
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, Volcani CenterBet Dagan50250Israel
| | - Michael Kravchik
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, Volcani CenterBet Dagan50250Israel
| | - Dalia Wolf
- Department of Vegetable and Field CropsAgricultural Research Organization, Volcani CenterBet Dagan50250Israel
| | - Sabrina Haviv
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, Volcani CenterBet Dagan50250Israel
| | - Mira Weissberg
- Department of Fruit Tree SciencesAgricultural Research Organization, Volcani CenterBet Dagan50250Israel
| | - Ron Ophir
- Department of Fruit Tree SciencesAgricultural Research Organization, Volcani CenterBet Dagan50250Israel
| | - Harry S. Paris
- Department of Vegetable Crops and Plant GeneticsAgricultural Research Organization, Newe Ya'ar Research Center, PO Box 1021RamatYishay30‐095Israel
| | - Peter Palukaitis
- Department of Horticultural SciencesSeoul Women's UniversityNowon‐guSeoul01797South Korea
| | - Shou‐Wei Ding
- Department of Plant Pathology and Microbiology & Institute for Integrative Genome BiologyUniversity of CaliforniaRiverside, CA92521USA
| | - Victor Gaba
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, Volcani CenterBet Dagan50250Israel
| | - Amit Gal‐On
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, Volcani CenterBet Dagan50250Israel
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Qin L, Mo N, Zhang Y, Muhammad T, Zhao G, Zhang Y, Liang Y. CaRDR1, an RNA-Dependent RNA Polymerase Plays a Positive Role in Pepper Resistance against TMV. FRONTIERS IN PLANT SCIENCE 2017; 8:1068. [PMID: 28702034 PMCID: PMC5487767 DOI: 10.3389/fpls.2017.01068] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 06/02/2017] [Indexed: 05/21/2023]
Abstract
RNA silencing functions as a major natural antiviral defense mechanism in plants. RNA-dependent RNA polymerases (RDRs) that catalyze the synthesis of double-stranded RNAs, are considered as a fundamental element in RNA silencing pathways. In Arabidopsis thaliana, RDR1, 2 and 6 play important roles in anti-viral RNA silencing. Expression of RDR1 can be elevated following plant treatment with defense hormones and virus infection. RDR1 has been studied in several crop species, but not in pepper (Capsicum annuum L.). Here, a RDR1 gene was isolated from Capsicum annuum L., designated as CaRDR1. The full-length cDNA of CaRDR1 was 3,351 bp, encoding a 1,116-amino acid protein, which contains conserved regions, such as the most remarkable motif DLDGD. The transcripts of CaRDR1 could be induced by salicylic acid (SA), abscisic acid (ABA), H2O2, and tobacco mosaic virus (TMV). Silencing of CaRDR1 in pepper resulted in increased susceptibility to TMV as evident by severe symptom, increased of TMV-CP transcript, higher malondialdehyde (MDA) content and lower antioxidant enzymes activities compared with that of control plants. CaRDR1-overexpressing in Nicotiana benthamiana showed mild disease symptom and reduced TMV-CP transcripts than that of empty vector (EV) following TMV inoculation. The RNA silencing related genes, including NbAGO2, NbDCL2, NbDCL3, and NbDCL4 elevated expression in overexpressed plants. Alternative oxidase (AOX), the terminal oxidase of the cyanide (CN)-resistant alternative respiratory pathway, catalyze oxygen-dependent oxidation of ubiquinol in plants. It has an important function in plant defense against TMV. In addition, CaRDR1 overexpression promoted the expression of NbAOX1a and NbAOX1b. In conclusion, these results suggest that CaRDR1 plays a positive role in TMV resistance by regulating antioxidant enzymes activities and RNA silencing-related genes expression to suppress the replication and movement of TMV.
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7
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Skandalis N, Dimopoulou A, Beri D, Tzima A, Malandraki I, Theologidis I, Bitivanos S, Varveri C, Klitsinaris T, Vassilakos N. Effect of Pyraclostrobin Application on Viral and Bacterial Diseases of Tomato. PLANT DISEASE 2016; 100:1321-1330. [PMID: 30686190 DOI: 10.1094/pdis-10-15-1216-re] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Quinone outside inhibitors (QoI) are powerful fungicides, which have been reported, additionally to their fungicide activity, to increase plant capacity to activate cellular defense responses and to promote plant growth. In this work, the effect of the QoI class fungicide pyraclostrobin was examined against Cucumber mosaic virus (CMV), Potato virus Y (PVY) and Pseudomonas syringae pv. tomato in tomato plants following artificial inoculation of the plants with the pathogens. Under controlled environmental conditions, pyraclostrobin delayed viral and bacterial disease development, even if P. syringae pv. tomato internal population levels were not affected significantly. In contrast, under field conditions in commercial greenhouses, a reduced CMV disease incidence throughout the tomato cultivation period was recorded. Gene expression analysis indicated an effect of pyraclostrobin application on tomato MAPKs transcript levels and a possible interference with plant stress responses.
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Affiliation(s)
- Nicholas Skandalis
- Department of Phytopathology, Benaki Phytopathological Institute, 145 61 Kifissia, Athens, Greece
| | - Anastasia Dimopoulou
- Department of Phytopathology, Benaki Phytopathological Institute, 145 61 Kifissia, Athens, Greece
| | - Despoina Beri
- Department of Phytopathology, Benaki Phytopathological Institute, 145 61 Kifissia, Athens, Greece
| | - Aliki Tzima
- Department of Phytopathology, Benaki Phytopathological Institute, 145 61 Kifissia, Athens, Greece
| | - Ioanna Malandraki
- Department of Phytopathology, Benaki Phytopathological Institute, 145 61 Kifissia, Athens, Greece
| | - Ioannis Theologidis
- Department of Phytopathology, Benaki Phytopathological Institute, 145 61 Kifissia, Athens, Greece
| | | | | | | | - Nikon Vassilakos
- Department of Phytopathology, Benaki Phytopathological Institute
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RNA-dependent RNA polymerase 1 in potato (Solanum tuberosum) and its relationship to other plant RNA-dependent RNA polymerases. Sci Rep 2016; 6:23082. [PMID: 26979928 PMCID: PMC4793286 DOI: 10.1038/srep23082] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/22/2016] [Indexed: 02/07/2023] Open
Abstract
Cellular RNA-dependent RNA polymerases (RDRs) catalyze synthesis of double-stranded RNAs that can serve to initiate or amplify RNA silencing. Arabidopsis thaliana has six RDR genes; RDRs 1, 2 and 6 have roles in anti-viral RNA silencing. RDR6 is constitutively expressed but RDR1 expression is elevated following plant treatment with defensive phytohormones. RDR1 also contributes to basal virus resistance. RDR1 has been studied in several species including A. thaliana, tobacco (Nicotiana tabacum), N. benthamiana, N. attenuata and tomato (Solanum lycopersicum) but not to our knowledge in potato (S. tuberosum). StRDR1 was identified and shown to be salicylic acid-responsive. StRDR1 transcript accumulation decreased in transgenic potato plants constitutively expressing a hairpin construct and these plants were challenged with three viruses: potato virus Y, potato virus X, and tobacco mosaic virus. Suppression of StRDR1 gene expression did not increase the susceptibility of potato to these viruses. Phylogenetic analysis of RDR genes present in potato and in a range of other plant species identified a new RDR gene family, not present in potato and found only in Rosids (but apparently lost in the Rosid A. thaliana) for which we propose the name RDR7.
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Lee WS, Fu SF, Li Z, Murphy AM, Dobson EA, Garland L, Chaluvadi SR, Lewsey MG, Nelson RS, Carr JP. Salicylic acid treatment and expression of an RNA-dependent RNA polymerase 1 transgene inhibit lethal symptoms and meristem invasion during tobacco mosaic virus infection in Nicotiana benthamiana. BMC PLANT BIOLOGY 2016; 16:15. [PMID: 26757721 PMCID: PMC4710973 DOI: 10.1186/s12870-016-0705-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/06/2016] [Indexed: 05/23/2023]
Abstract
BACKGROUND Host RNA-dependent RNA polymerases (RDRs) 1 and 6 contribute to antiviral RNA silencing in plants. RDR6 is constitutively expressed and was previously shown to limit invasion of Nicotiana benthamiana meristem tissue by potato virus X and thereby inhibit disease development. RDR1 is inducible by salicylic acid (SA) and several other phytohormones. But although it contributes to basal resistance to tobacco mosaic virus (TMV) it is dispensable for SA-induced resistance in inoculated leaves. The laboratory accession of N. benthamiana is a natural rdr1 mutant and highly susceptible to TMV. However, TMV-induced symptoms are ameliorated in transgenic plants expressing Medicago truncatula RDR1. RESULTS In MtRDR1-transgenic N. benthamiana plants the spread of TMV expressing the green fluorescent protein (TMV.GFP) into upper, non-inoculated, leaves was not inhibited. However, in these plants exclusion of TMV.GFP from the apical meristem and adjacent stem tissue was greater than in control plants and this exclusion effect was enhanced by SA. TMV normally kills N. benthamiana plants but although MtRDR1-transgenic plants initially displayed virus-induced necrosis they subsequently recovered. Recovery from disease was markedly enhanced by SA treatment in MtRDR1-transgenic plants whereas in control plants SA delayed but did not prevent systemic necrosis and death. Following SA treatment of MtRDR1-transgenic plants, extractable RDR enzyme activity was increased and Western blot analysis of RDR extracts revealed a band cross-reacting with an antibody raised against MtRDR1. Expression of MtRDR1 in the transgenic N. benthamiana plants was driven by a constitutive 35S promoter derived from cauliflower mosaic virus, confirmed to be non-responsive to SA. This suggests that the effects of SA on MtRDR1 are exerted at a post-transcriptional level. CONCLUSIONS MtRDR1 inhibits severe symptom development by limiting spread of virus into the growing tips of infected plants. Thus, RDR1 may act in a similar fashion to RDR6. MtRDR1 and SA acted additively to further promote recovery from disease symptoms in MtRDR1-transgenic plants. Thus it is possible that SA promotes MtRDR1 activity and/or stability through post-transcriptional effects.
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Affiliation(s)
- Wing-Sham Lee
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
| | - Shih-Feng Fu
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
- Department of Biology, National Changhua University of Education, 1 Jin-De Road, Changhua City, 500, Taiwan.
| | - Zheng Li
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
| | - Alex M Murphy
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
| | - Elizabeth A Dobson
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
| | - Laura Garland
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
| | - Srinivasa Rao Chaluvadi
- Plant Biology Division, Samuel Roberts Noble Foundation, Inc, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA.
| | - Mathew G Lewsey
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
- Centre for AgriBioscience, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Australia.
| | - Richard S Nelson
- Plant Biology Division, Samuel Roberts Noble Foundation, Inc, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA.
| | - John P Carr
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
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Hong W, Qian D, Sun R, Jiang L, Wang Y, Wei C, Zhang Z, Li Y. OsRDR6 plays role in host defense against double-stranded RNA virus, Rice Dwarf Phytoreovirus. Sci Rep 2015; 5:11324. [PMID: 26165755 PMCID: PMC4499934 DOI: 10.1038/srep11324] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/13/2015] [Indexed: 11/29/2022] Open
Abstract
RNAi is a major antiviral defense response in plant and animal model systems. RNA-dependent RNA polymerase 6 (RDR6) is an essential component of RNAi, which plays an important role in the resistance against viruses in the model plants. We found previously that rice RDR6 (OsRDR6) functioned in the defense against Rice stripe virus (RSV), and Rice Dwarf Phytoreovirus (RDV) infection resulted in down-regulation of expression of RDR6. Here we report our new findings on the function of OsRDR6 against RDV. Our result showed that down-regulation of OsRDR6 through the antisense (OsRDR6AS) strategy increased rice susceptibility to RDV infection while over-expression of OsRDR6 had no effect on RDV infection. The accumulation of RDV vsiRNAs was reduced in the OsRDR6AS plants. In the OsRDR6 over-expressed plants, the levels of OsRDR6 RNA transcript and protein were much higher than that in the control plants. Interestingly, the accumulation level of OsRDR6 protein became undetectable after RDV infection. This finding indicated that the translation and/or stability of OsRDR6 protein were negatively impacted upon RDV infection. This new finding provides a new light on the function of RDR6 in plant defense response and the cross-talking between factors encoded by host plant and double-stranded RNA viruses.
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Affiliation(s)
- Wei Hong
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Dan Qian
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Runhong Sun
- 1] State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China [2] Institute of Plant Protection, Henan Academy of Agricultural Sciences, Henan Key Laboratory of Crop Pest Control, Zhengzhou 450002, China
| | - Lin Jiang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Yu Wang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Chunhong Wei
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Zhongkai Zhang
- Ministry of Agriculture Key Lab of Southwestern Crop Gene Resources and Germplasm Innovation, Yunnan Provincial Key Lab of Agricultural Biotechnology, Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650223, China
| | - Yi Li
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
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11
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Li Z, Liang WS, Carr JP. Effects of modifying alternative respiration on nitric oxide-induced virus resistance and PR1 protein accumulation. J Gen Virol 2014; 95:2075-2081. [PMID: 24903327 DOI: 10.1099/vir.0.066662-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
Nitric oxide (NO) is an important defensive signal in plants but its effects on virus infection are not well understood. Administration of NO-releasing compounds immediately before inoculation of tobacco leaves with potato virus X and tobacco mosaic virus decreased the accumulation of virus, indicating that NO can induce resistance rapidly. Resistance induction was inhibited by co-administration with an NO-scavenging compound or when experiments were done in transgenic tobacco plants expressing increased alternative respiratory pathway capacity due to constitutive expression of the plant mitochondrial enzyme, alternative oxidase (AOX). These results indicate that NO, which inhibits electron transport chain activity, is triggering defensive signalling by inducing changes in mitochondrial reactive oxygen species levels that are in turn regulated by AOX. Experiments using nahG-transgenic plants, which cannot accumulate the defensive plant hormone salicylic acid (SA) showed that NO rapidly induces resistance to virus infection independently of SA. However, this initial state of resistance may be transient. Subsequently, by 5 days post-treatment, NO had caused an increase in pathogenesis-related protein 1 (PR1) expression (a proxy for increased SA biosynthesis), which correlated with a longer-term state of resistance to virus infection. The induction by NO of PR1 accumulation was modified in AOX-transgenic plants. This indicates that the influence of NO on defensive gene expression is in part mediated through its effects on mitochondria.
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Affiliation(s)
- Zheng Li
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
| | - Wu-Sheng Liang
- Institute of Biotechnology, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
| | - John P Carr
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
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