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Naim D, Ahsan A, Imtiaj A, Mollah NH. Genome-wide identification and in silico characterization of major RNAi gene families in date palm (Phoenix dactylifera). BMC Genom Data 2024; 25:31. [PMID: 38491426 PMCID: PMC10943882 DOI: 10.1186/s12863-024-01217-x] [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: 05/13/2023] [Accepted: 03/06/2024] [Indexed: 03/18/2024] Open
Abstract
BACKGROUND Dates contain various minerals that are essential for good health. The major RNA interference (RNAi) gene families play a vital role in plant growth and development by controlling the expression of protein-coding genes against different biotic and abiotic stresses. However, these gene families for date palm are not yet studied. Therefore, this study has explored major RNAi genes and their characteristics in date palm. RESULTS We have identified 4 PdDCLs, 7 PdAGOs, and 3 PdRDRs as RNAi proteins from the date palm genome by using AtRNAi genes as query sequences in BLASTp search. Domain analysis of predicted RNAi genes has revealed the Helicase_C, Dicer_dimer, PAZ, RNase III, and Piwi domains that are associated with the gene silencing mechanisms. Most PdRNAi proteins have been found in the nucleus and cytosol associated with the gene silencing actions. The gene ontology (GO) enrichment analysis has revealed some important GO terms including RNA interference, dsRNA fragmentation, and ribonuclease_III activity that are related to the protein-coding gene silencing mechanisms. Gene regulatory network (GRN) analysis has identified PAZ and SNF2 as the transcriptional regulators of PdRNAi genes. Top-ranked 10 microRNAs including Pda-miR156b, Pda-miR396a, Pda-miR166a, Pda-miR167d, and Pda-miR529a have been identified as the key post-transcriptional regulators of PdRNAi genes that are associated with different biotic/abiotic stresses. The cis-acting regulatory element analysis of PdRNAi genes has detected some vital cis-acting elements including ABRE, MBS, MYB, MYC, Box-4, G-box, I-box, and STRE that are linked with different abiotic stresses. CONCLUSION The results of this study might be valuable resources for the improvement of different characteristics in date palm by further studies in wet-lab.
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Affiliation(s)
- Darun Naim
- Bioinformatics Lab, Department of Statistics, Faculty of Science, University of Rajshahi, 6205, Rajshahi, Bangladesh
- Department of Botany, Faculty of Biological Sciences, University of Rajshahi, 6205, Rajshahi, Bangladesh
| | - Asif Ahsan
- Bioinformatics Lab, Department of Statistics, Faculty of Science, University of Rajshahi, 6205, Rajshahi, Bangladesh
| | - Ahmed Imtiaj
- Department of Botany, Faculty of Biological Sciences, University of Rajshahi, 6205, Rajshahi, Bangladesh
| | - Nurul Haque Mollah
- Bioinformatics Lab, Department of Statistics, Faculty of Science, University of Rajshahi, 6205, Rajshahi, Bangladesh.
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Hasan MN, Mosharaf MP, Uddin KS, Das KR, Sultana N, Noorunnahar M, Naim D, Mollah MNH. Genome-Wide Identification and Characterization of Major RNAi Genes Highlighting Their Associated Factors in Cowpea ( Vigna unguiculata (L.) Walp.). BIOMED RESEARCH INTERNATIONAL 2023; 2023:8832406. [PMID: 38046903 PMCID: PMC10691899 DOI: 10.1155/2023/8832406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/07/2023] [Accepted: 10/30/2023] [Indexed: 12/05/2023]
Abstract
In different regions of the world, cowpea (Vigna unguiculata (L.) Walp.) is an important vegetable and an excellent source of protein. It lessens the malnutrition of the underprivileged in developing nations and has some positive effects on health, such as a reduction in the prevalence of cancer and cardiovascular disease. However, occasionally, certain biotic and abiotic stresses caused a sharp fall in cowpea yield. Major RNA interference (RNAi) genes like Dicer-like (DCL), Argonaute (AGO), and RNA-dependent RNA polymerase (RDR) are essential for the synthesis of their associated factors like domain, small RNAs (sRNAs), transcription factors, micro-RNAs, and cis-acting factors that shield plants from biotic and abiotic stresses. In this study, applying BLASTP search and phylogenetic tree analysis with reference to the Arabidopsis RNAi (AtRNAi) genes, we discovered 28 VuRNAi genes, including 7 VuDCL, 14 VuAGO, and 7 VuRDR genes in cowpea. We looked at the domains, motifs, gene structures, chromosomal locations, subcellular locations, gene ontology (GO) terms, and regulatory factors (transcription factors, micro-RNAs, and cis-acting elements (CAEs)) to characterize the VuRNAi genes and proteins in cowpea in response to stresses. Predicted VuDCL1, VuDCL2(a, b), VuAGO7, VuAGO10, and VuRDR6 genes might have an impact on cowpea growth, development of the vegetative and flowering stages, and antiviral defense. The VuRNAi gene regulatory features miR395 and miR396 might contribute to grain quality improvement, immunity boosting, and pathogen infection resistance under salinity and drought conditions. Predicted CAEs from the VuRNAi genes might play a role in plant growth and development, improving grain quality and production and protecting plants from biotic and abiotic stresses. Therefore, our study provides crucial information about the functional roles of VuRNAi genes and their associated components, which would aid in the development of future cowpeas that are more resilient to biotic and abiotic stress. The manuscript is available as a preprint at this link: doi:10.1101/2023.02.15.528631v1.
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Affiliation(s)
- Mohammad Nazmol Hasan
- Department of Statistics, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh
| | - Md Parvez Mosharaf
- School of Business, Faculty of Business, Education, Law and Arts, University of Southern Queensland, Toowoomba, QLD 4350, Australia
| | - Khandoker Saif Uddin
- Department of Quantitative Science (Statistics), International University of Business Agriculture and Technology (IUBAT), Uttara, Bangladesh
| | - Keya Rani Das
- Department of Statistics, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh
| | - Nasrin Sultana
- Department of Statistics, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh
| | - Mst. Noorunnahar
- Department of Statistics, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh
| | - Darun Naim
- Department of Botany, Faculty of Biological Sciences, University of Rajshahi, Rajshahi 6205, Bangladesh
- Bioinformatics Lab, Department of Statistics, Faculty of Science, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Md. Nurul Haque Mollah
- Bioinformatics Lab, Department of Statistics, Faculty of Science, University of Rajshahi, Rajshahi 6205, Bangladesh
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Vermeulen A, Takken FLW, Sánchez-Camargo VA. Translation Arrest: A Key Player in Plant Antiviral Response. Genes (Basel) 2023; 14:1293. [PMID: 37372472 DOI: 10.3390/genes14061293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
Plants evolved several mechanisms to protect themselves against viruses. Besides recessive resistance, where compatible host factors required for viral proliferation are absent or incompatible, there are (at least) two types of inducible antiviral immunity: RNA silencing (RNAi) and immune responses mounted upon activation of nucleotide-binding domain leucine-rich repeat (NLR) receptors. RNAi is associated with viral symptom recovery through translational repression and transcript degradation following recognition of viral double-stranded RNA produced during infection. NLR-mediated immunity is induced upon (in)direct recognition of a viral protein by an NLR receptor, triggering either a hypersensitive response (HR) or an extreme resistance response (ER). During ER, host cell death is not apparent, and it has been proposed that this resistance is mediated by a translational arrest (TA) of viral transcripts. Recent research indicates that translational repression plays a crucial role in plant antiviral resistance. This paper reviews current knowledge on viral translational repression during viral recovery and NLR-mediated immunity. Our findings are summarized in a model detailing the pathways and processes leading to translational arrest of plant viruses. This model can serve as a framework to formulate hypotheses on how TA halts viral replication, inspiring new leads for the development of antiviral resistance in crops.
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Affiliation(s)
- Annemarie Vermeulen
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences (SILS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Frank L W Takken
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences (SILS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Victor A Sánchez-Camargo
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences (SILS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
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Malavika M, Prakash V, Chakraborty S. Recovery from virus infection: plant's armory in action. PLANTA 2023; 257:103. [PMID: 37115475 DOI: 10.1007/s00425-023-04137-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 04/14/2023] [Indexed: 05/26/2023]
Abstract
MAIN CONCLUSION This review focuses on different factors involved in promoting symptom recovery in plants post-virus infection such as epigenetics, transcriptional reprogramming, phytohormones with an emphasis on RNA silencing as well as role of abiotic factors such as temperature on symptom recovery. Plants utilize several different strategies to defend themselves in the battle against invading viruses. Most of the viral proteins interact with plant proteins and interfere with molecular dynamics in a cell which eventually results in symptom development. This initial symptom development is countered by the plant utilizing various factors including the plant's adaptive immunity to develop a virus tolerant state. Infected plants can specifically target and impede the transcription of viral genes as well as degrade the viral transcripts to restrict their proliferation by the production of small-interfering RNA (siRNA) generated from the viral nucleic acid, known as virus-derived siRNA (vsiRNA). To further escalate the degradation of viral nucleic acid, secondary siRNAs are generated. The production of virus-activated siRNA (vasiRNA) from the host genome causes differential regulation of the host transcriptome which plays a major role in establishing a virus tolerant state within the infected plant. The systemic action of vsiRNAs, vasiRNA, and secondary siRNAs with the help of defense hormones like salicylic acid can curb viral proliferation, and thus the newly emerged leaves develop fewer symptoms, maintaining a state of tolerance.
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Affiliation(s)
- M Malavika
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Ved Prakash
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
- Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506, USA
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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Choi J, Osatuke AC, Erich G, Stevens K, Hwang MS, Al Rwahnih M, Fuchs M. High-Throughput Sequencing Reveals Tobacco and Tomato Ringspot Viruses in Pawpaw. PLANTS (BASEL, SWITZERLAND) 2022; 11:3565. [PMID: 36559676 PMCID: PMC9782031 DOI: 10.3390/plants11243565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/13/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
Pawpaw (Asimina triloba) trees exhibiting stunting and foliar mosaic, chlorosis, or distortions were observed in New York. In 2021, leaf samples from two symptomatic trees and a sapling, as well as two asymptomatic trees, were tested for the presence of viruses and viroids by high-throughput sequencing (HTS) using total RNA after ribosomal RNA depletion. HTS sequence information revealed tobacco ringspot virus (TRSV) and tomato ringspot virus (ToRSV) in symptomatic but not in asymptomatic leaves. HTS reads and de novo-assembled contigs covering the genomes of both viruses were obtained, with a higher average read depth for RNA2 than RNA1. The occurrence of TRSV and ToRSV was confirmed in the original leaf samples used for HTS and 12 additional trees and saplings from New York and Maryland in 2022 by RT-PCR combined with Sanger sequencing, and DAS-ELISA. Single infections by TRSV in 11 of 14 trees and dual infections by TRSV and ToRSV in 3 of 14 trees were identified. The nucleotide sequence identity of partial gene fragments of TRSV and ToRSV was high among pawpaw isolates (94.9-100% and 91.8-100%, respectively) and between pawpaw isolates and isolates from other horticultural crops (93.6-100% and 71.3-99.3%, respectively). This study is the first to determine the virome of pawpaw.
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Affiliation(s)
- Jiyeong Choi
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, NY 14456, USA
| | - Anya Clara Osatuke
- Cornell Cooperative Extension, Cornell University, Ithaca, NY 14853, USA
| | - Griffin Erich
- School of Integrative Plant Science, Horticulture, Cornell University, Ithaca, NY 14853, USA
| | - Kristian Stevens
- Department of Plant Pathology, Foundation Plant Services, University of California, Davis, CA 95616, USA
| | - Min Sook Hwang
- Department of Plant Pathology, Foundation Plant Services, University of California, Davis, CA 95616, USA
| | - Maher Al Rwahnih
- Department of Plant Pathology, Foundation Plant Services, University of California, Davis, CA 95616, USA
| | - Marc Fuchs
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, NY 14456, USA
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Comprehensive In Silico Analysis of RNA Silencing-Related Genes and Their Regulatory Elements in Wheat (Triticum aestivum L.). BIOMED RESEARCH INTERNATIONAL 2022; 2022:4955209. [PMID: 36177060 PMCID: PMC9513535 DOI: 10.1155/2022/4955209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 08/09/2022] [Accepted: 08/13/2022] [Indexed: 11/17/2022]
Abstract
Dicer-like (DCL), Argonaute (AGO), and RNA-dependent RNA polymerase (RDR) are known as the three major gene families that act as the critical components of RNA interference or silencing mechanisms through the noncoding small RNA molecules (miRNA and siRNA) to regulate the expressions of protein-coding genes in eukaryotic organisms. However, most of their characteristics including structures, chromosomal location, subcellular locations, regulatory elements, and gene networking were not rigorously studied. Our analysis identified 7 TaDCL, 39 TaAGO, and 16 TaRDR genes as RNA interference (RNAi) genes from the wheat genome. Phylogenetic analysis of predicted RNAi proteins with the RNAi proteins of Arabidopsis and rice showed that the predicted proteins of TaDCL, TaAGO, and TaRDR groups are clustered into four, eight, and four subgroups, respectively. Domain, 3D protein structure, motif, and exon-intron structure analyses showed that these proteins conserve identical characteristics within groups and maintain differences between groups. The nonsynonymous/synonymous mutation ratio (Ka/Ks) < 1 suggested that these protein sequences conserve some purifying functions. RNAi genes networking with TFs revealed that ERF, MIKC-MADS, C2H2, BBR-BPC, MYB, and Dof are the key transcriptional regulators of the predicted RNAi-related genes. The cis-regulatory element (CREs) analysis detected some important CREs of RNAi genes that are significantly associated with light, stress, and hormone responses. Expression analysis based on an online database exhibited that almost all of the predicted RNAi genes are expressed in different tissues and organs. A case-control study from the gene expression level showed that some RNAi genes significantly responded to the drought and heat stresses. Overall results would therefore provide an excellent basis for in-depth molecular investigation of these genes and their regulatory elements for wheat crop improvement against different stressors.
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Wang C, Jiang F, Zhu S. Complex Small RNA-mediated Regulatory Networks between Viruses/Viroids/Satellites and Host Plants. Virus Res 2022; 311:198704. [DOI: 10.1016/j.virusres.2022.198704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 01/16/2022] [Accepted: 01/29/2022] [Indexed: 12/26/2022]
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Ahmed FF, Hossen MI, Sarkar MAR, Konak JN, Zohra FT, Shoyeb M, Mondal S. Genome-wide identification of DCL, AGO and RDR gene families and their associated functional regulatory elements analyses in banana (Musa acuminata). PLoS One 2021; 16:e0256873. [PMID: 34473743 PMCID: PMC8412350 DOI: 10.1371/journal.pone.0256873] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 08/17/2021] [Indexed: 12/15/2022] Open
Abstract
RNA silencing is mediated through RNA interference (RNAi) pathway gene families, i.e., Dicer-Like (DCL), Argonaute (AGO), and RNA-dependent RNA polymerase (RDR) and their cis-acting regulatory elements. The RNAi pathway is also directly connected with the post-transcriptional gene silencing (PTGS) mechanism, and the pathway controls eukaryotic gene regulation during growth, development, and stress response. Nevertheless, genome-wide identification of RNAi pathway gene families such as DCL, AGO, and RDR and their regulatory network analyses related to transcription factors have not been studied in many fruit crop species, including banana (Musa acuminata). In this study, we studied in silico genome-wide identification and characterization of DCL, AGO, and RDR genes in bananas thoroughly via integrated bioinformatics approaches. A genome-wide analysis identified 3 MaDCL, 13 MaAGO, and 5 MaRDR candidate genes based on multiple sequence alignment and phylogenetic tree related to the RNAi pathway in banana genomes. These genes correspond to the Arabidopsis thaliana RNAi silencing genes. The analysis of the conserved domain, motif, and gene structure (exon-intron numbers) for MaDCL, MaAGO, and MaRDR genes showed higher homogeneity within the same gene family. The Gene Ontology (GO) enrichment analysis exhibited that the identified RNAi genes could be involved in RNA silencing and associated metabolic pathways. A number of important transcription factors (TFs), e.g., ERF, Dof, C2H2, TCP, GATA and MIKC_MADS families, were identified by network and sub-network analyses between TFs and candidate RNAi gene families. Furthermore, the cis-acting regulatory elements related to light-responsive (LR), stress-responsive (SR), hormone-responsive (HR), and other activities (OT) functions were identified in candidate MaDCL, MaAGO, and MaRDR genes. These genome-wide analyses of these RNAi gene families provide valuable information related to RNA silencing, which would shed light on further characterization of RNAi genes, their regulatory elements, and functional roles, which might be helpful for banana improvement in the breeding program.
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Affiliation(s)
- Fee Faysal Ahmed
- Faculty of Science, Department of Mathematics, Jashore University of Science and Technology, Jashore, Bangladesh
- * E-mail:
| | - Md. Imran Hossen
- Faculty of Science, Department of Mathematics, Jashore University of Science and Technology, Jashore, Bangladesh
| | - Md. Abdur Rauf Sarkar
- Faculty of Biological Science and Technology, Department of Genetic Engineering and Biotechnology, Jashore University of Science and Technology, Jashore, Bangladesh
| | - Jesmin Naher Konak
- Faculty of Life Science, Department of Biochemistry and Molecular Biology, Mawlana Bhashani Science and Technology University, Tangail, Bangladesh
| | - Fatema Tuz Zohra
- Faculty of Agriculture, Laboratory of Fruit Science, Saga University, Honjo-machi, Saga, Japan
| | - Md. Shoyeb
- Faculty of Biological Science and Technology, Department of Genetic Engineering and Biotechnology, Jashore University of Science and Technology, Jashore, Bangladesh
| | - Samiran Mondal
- Faculty of Science, Department of Mathematics, Jashore University of Science and Technology, Jashore, Bangladesh
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Osterbaan LJ, Hoyle V, Curtis M, DeBlasio S, Rivera KD, Heck M, Fuchs M. Identification of protein interactions of grapevine fanleaf virus RNA-dependent RNA polymerase during infection of Nicotiana benthamiana by affinity purification and tandem mass spectrometry. J Gen Virol 2021; 102:001607. [PMID: 34043500 PMCID: PMC8295916 DOI: 10.1099/jgv.0.001607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/07/2021] [Indexed: 11/24/2022] Open
Abstract
The RNA-dependent RNA polymerase (1EPol) is involved in replication of grapevine fanleaf virus (GFLV, Nepovirus, Secoviridae) and causes vein clearing symptoms in Nicotiana benthamiana. Information on protein 1EPol interaction with other viral and host proteins is scarce. To study protein 1EPol biology, three GFLV infectious clones, i.e. GHu (a symptomatic wild-type strain), GHu-1EK802G (an asymptomatic GHu mutant) and F13 (an asymptomatic wild-type strain), were engineered with protein 1EPol fused to a V5 epitope tag at the C-terminus. Following Agrobacterium tumefaciens-mediated delivery of GFLV clones in N. benthamiana and protein extraction at seven dpi, when optimal 1EPol:V5 accumulation was detected, two viral and six plant putative interaction partners of V5-tagged protein 1EPol were identified for the three GFLV clones by affinity purification and tandem mass spectrometry. This study provides insights into the protein interactome of 1EPol during GFLV systemic infection in N. benthamiana and lays the foundation for validation work.
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Affiliation(s)
- Larissa J. Osterbaan
- Cornell University, Plant Pathology and Plant Microbe-Biology Section, School of Integrative Plant Science, Cornell AgriTech at the New York State Agricultural Experiment Station, Geneva, NY 14456, USA
- Present address: Department of Biology, Utica College, Utica, NY 13502, USA
| | - Victoria Hoyle
- Cornell University, Plant Pathology and Plant Microbe-Biology Section, School of Integrative Plant Science, Cornell AgriTech at the New York State Agricultural Experiment Station, Geneva, NY 14456, USA
| | - Michelle Curtis
- Cornell University, Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Ithaca, NY 14853, USA
| | - Stacy DeBlasio
- Emerging Pests and Pathogens Research Unit, USDA Agricultural Research Service, Robert W. Holley Center for Agriculture and Health, Ithaca, NY 14853, USA
| | - Keith D. Rivera
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
- Present address: The Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142, USA
| | - Michelle Heck
- Cornell University, Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Ithaca, NY 14853, USA
- Emerging Pests and Pathogens Research Unit, USDA Agricultural Research Service, Robert W. Holley Center for Agriculture and Health, Ithaca, NY 14853, USA
| | - Marc Fuchs
- Cornell University, Plant Pathology and Plant Microbe-Biology Section, School of Integrative Plant Science, Cornell AgriTech at the New York State Agricultural Experiment Station, Geneva, NY 14456, USA
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Ramesh SV, Yogindran S, Gnanasekaran P, Chakraborty S, Winter S, Pappu HR. Virus and Viroid-Derived Small RNAs as Modulators of Host Gene Expression: Molecular Insights Into Pathogenesis. Front Microbiol 2021; 11:614231. [PMID: 33584579 PMCID: PMC7874048 DOI: 10.3389/fmicb.2020.614231] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 11/19/2020] [Indexed: 02/01/2023] Open
Abstract
Virus-derived siRNAs (vsiRNAs) generated by the host RNA silencing mechanism are effectors of plant’s defense response and act by targeting the viral RNA and DNA in post-transcriptional gene silencing (PTGS) and transcriptional gene silencing (TGS) pathways, respectively. Contrarily, viral suppressors of RNA silencing (VSRs) compromise the host RNA silencing pathways and also cause disease-associated symptoms. In this backdrop, reports describing the modulation of plant gene(s) expression by vsiRNAs via sequence complementarity between viral small RNAs (sRNAs) and host mRNAs have emerged. In some cases, silencing of host mRNAs by vsiRNAs has been implicated to cause characteristic symptoms of the viral diseases. Similarly, viroid infection results in generation of sRNAs, originating from viroid genomic RNAs, that potentially target host mRNAs causing typical disease-associated symptoms. Pathogen-derived sRNAs have been demonstrated to have the propensity to target wide range of genes including host defense-related genes, genes involved in flowering and reproductive pathways. Recent evidence indicates that vsiRNAs inhibit host RNA silencing to promote viral infection by acting as decoy sRNAs. Nevertheless, it remains unclear if the silencing of host transcripts by viral genome-derived sRNAs are inadvertent effects due to fortuitous pairing between vsiRNA and host mRNA or the result of genuine counter-defense strategy employed by viruses to enhance its survival inside the plant cell. In this review, we analyze the instances of such cross reaction between pathogen-derived vsiRNAs and host mRNAs and discuss the molecular insights regarding the process of pathogenesis.
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Affiliation(s)
- S V Ramesh
- ICAR-Central Plantation Crops Research Institute, Kasaragod, India
| | - Sneha Yogindran
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Prabu Gnanasekaran
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
| | | | - Stephan Winter
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Braunschweig, Germany
| | - Hanu R Pappu
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
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11
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Mosharaf MP, Rahman H, Ahsan MA, Akond Z, Ahmed FF, Islam MM, Moni MA, Mollah MNH. In silico identification and characterization of AGO, DCL and RDR gene families and their associated regulatory elements in sweet orange (Citrus sinensis L.). PLoS One 2020; 15:e0228233. [PMID: 33347517 PMCID: PMC7751981 DOI: 10.1371/journal.pone.0228233] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 12/07/2020] [Indexed: 12/30/2022] Open
Abstract
RNA interference (RNAi) plays key roles in post-transcriptional and chromatin modification levels as well as regulates various eukaryotic gene expressions which are involved in stress responses, development and maintenance of genome integrity during developmental stages. The whole mechanism of RNAi pathway is directly involved with the gene-silencing process by the interaction of Dicer-Like (DCL), Argonaute (AGO) and RNA-dependent RNA polymerase (RDR) gene families and their regulatory elements. However, these RNAi gene families and their sub-cellular locations, functional pathways and regulatory components were not extensively investigated in the case of economically and nutritionally important fruit plant sweet orange (Citrus sinensis L.). Therefore, in silico characterization, gene diversity and regulatory factor analysis of RNA silencing genes in C. sinensis were conducted by using the integrated bioinformatics approaches. Genome-wide comparison analysis based on phylogenetic tree approach detected 4 CsDCL, 8 CsAGO and 4 CsRDR as RNAi candidate genes in C. sinensis corresponding to the RNAi genes of model plant Arabidopsis thaliana. The domain and motif composition and gene structure analyses for all three gene families exhibited almost homogeneity within the same group members. The Gene Ontology enrichment analysis clearly indicated that the predicted genes have direct involvement into the gene-silencing and other important pathways. The key regulatory transcription factors (TFs) MYB, Dof, ERF, NAC, MIKC_MADS, WRKY and bZIP were identified by their interaction network analysis with the predicted genes. The cis-acting regulatory elements associated with the predicted genes were detected as responsive to light, stress and hormone functions. Furthermore, the expressed sequence tag (EST) analysis showed that these RNAi candidate genes were highly expressed in fruit and leaves indicating their organ specific functions. Our genome-wide comparison and integrated bioinformatics analyses provided some necessary information about sweet orange RNA silencing components that would pave a ground for further investigation of functional mechanism of the predicted genes and their regulatory factors.
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Affiliation(s)
- Md. Parvez Mosharaf
- Bioinformatics Laboratory, Department of Statistics, University of Rajshahi, Rajshahi, Bangladesh
| | - Hafizur Rahman
- Department of Microbiology, Rajshahi Institute of Biosciences, University of Rajshahi, Rajshahi, Bangladesh
| | - Md. Asif Ahsan
- Bioinformatics Laboratory, Department of Statistics, University of Rajshahi, Rajshahi, Bangladesh
| | - Zobaer Akond
- Bioinformatics Laboratory, Department of Statistics, University of Rajshahi, Rajshahi, Bangladesh
- Institute of Environmental Science, University of Rajshahi, Rajshahi, Bangladesh
- Agricultural Statistics and ICT Division, Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh
| | - Fee Faysal Ahmed
- Bioinformatics Laboratory, Department of Statistics, University of Rajshahi, Rajshahi, Bangladesh
- Department of Mathematics, Jashore University of Science and Technology, Jashore, Bangladesh
| | - Md. Mazharul Islam
- Bioinformatics Laboratory, Department of Statistics, University of Rajshahi, Rajshahi, Bangladesh
| | - Mohammad Ali Moni
- The University of Sydney, Sydney Medical School, School of Medical Sciences, Discipline of Biomedical Science, Sydney, New South Wales, Australia
| | - Md. Nurul Haque Mollah
- Bioinformatics Laboratory, Department of Statistics, University of Rajshahi, Rajshahi, Bangladesh
- * E-mail:
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12
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Sanfaçon H. Modulation of disease severity by plant positive-strand RNA viruses: The complex interplay of multifunctional viral proteins, subviral RNAs and virus-associated RNAs with plant signaling pathways and defense responses. Adv Virus Res 2020; 107:87-131. [PMID: 32711736 DOI: 10.1016/bs.aivir.2020.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Plant viruses induce a range of symptoms of varying intensity, ranging from severe systemic necrosis to mild or asymptomatic infection. Several evolutionary constraints drive virus virulence, including the dependence of viruses on host factors to complete their infection cycle, the requirement to counteract or evade plant antiviral defense responses and the mode of virus transmission. Viruses have developed an array of strategies to modulate disease severity. Accumulating evidence has highlighted not only the multifunctional role that viral proteins play in disrupting or highjacking plant factors, hormone signaling pathways and intracellular organelles, but also the interaction networks between viral proteins, subviral RNAs and/or other viral-associated RNAs that regulate disease severity. This review focusses on positive-strand RNA viruses, which constitute the majority of characterized plant viruses. Using well-characterized viruses with different genome types as examples, recent advances are discussed as well as knowledge gaps and opportunities for further research.
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Affiliation(s)
- Hélène Sanfaçon
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, BC, Canada.
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13
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Miozzi L, Vaira AM, Brilli F, Casarin V, Berti M, Ferrandino A, Nerva L, Accotto GP, Lanfranco L. Arbuscular Mycorrhizal Symbiosis Primes Tolerance to Cucumber Mosaic Virus in Tomato. Viruses 2020; 12:E675. [PMID: 32580438 PMCID: PMC7354615 DOI: 10.3390/v12060675] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/19/2020] [Accepted: 06/20/2020] [Indexed: 01/30/2023] Open
Abstract
Tomato plants can establish symbiotic interactions with arbuscular mycorrhizal fungi (AMF) able to promote plant nutrition and prime systemic plant defenses against pathogens attack; the mechanism involved is known as mycorrhiza-induced resistance (MIR). However, studies on the effect of AMF on viral infection, still limited and not conclusive, indicate that AMF colonization may have a detrimental effect on plant defenses against viruses, so that the term "mycorrhiza-induced susceptibility" (MIS) has been proposed for these cases. To expand the case studies to a not yet tested viral family, that is, Bromoviridae, we investigated the effect of the colonization by the AMF Funneliformis mosseae on cucumber mosaic virus (CMV) infection in tomato by phenotypic, physiological, biochemical, and transcriptional analyses. Our results showed that the establishment of a functional AM symbiosis is able to limit symptoms development. Physiological and transcriptomic data highlighted that AMF mitigates the drastic downregulation of photosynthesis-related genes and the reduction of photosynthetic CO2 assimilation rate caused by CMV infection. In parallel, an increase of salicylic acid level and a modulation of reactive oxygen species (ROS)-related genes, toward a limitation of ROS accumulation, was specifically observed in CMV-infected mycorrhizal plants. Overall, our data indicate that the AM symbiosis influences the development of CMV infection in tomato plants and exerts a priming effect able to enhance tolerance to viral infection.
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Affiliation(s)
- Laura Miozzi
- Institute for Sustainable Plant Protection, National Research Council of Italy (IPSP-CNR), Torino, Strada delle Cacce 73, 10135 Torino, Italy; (A.M.V.); (V.C.); (M.B.); (L.N.); (G.P.A.)
| | - Anna Maria Vaira
- Institute for Sustainable Plant Protection, National Research Council of Italy (IPSP-CNR), Torino, Strada delle Cacce 73, 10135 Torino, Italy; (A.M.V.); (V.C.); (M.B.); (L.N.); (G.P.A.)
| | - Federico Brilli
- Institute for Sustainable Plant Protection, National Research Council of Italy (IPSP-CNR), Unit of Sesto Fiorentino (FI), Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy;
| | - Valerio Casarin
- Institute for Sustainable Plant Protection, National Research Council of Italy (IPSP-CNR), Torino, Strada delle Cacce 73, 10135 Torino, Italy; (A.M.V.); (V.C.); (M.B.); (L.N.); (G.P.A.)
| | - Mara Berti
- Institute for Sustainable Plant Protection, National Research Council of Italy (IPSP-CNR), Torino, Strada delle Cacce 73, 10135 Torino, Italy; (A.M.V.); (V.C.); (M.B.); (L.N.); (G.P.A.)
| | - Alessandra Ferrandino
- Department of Agricultural, Forestry and Food Sciences, University of Torino, Largo Paolo Braccini 2, 10095 Grugliasco (TO), Italy;
| | - Luca Nerva
- Institute for Sustainable Plant Protection, National Research Council of Italy (IPSP-CNR), Torino, Strada delle Cacce 73, 10135 Torino, Italy; (A.M.V.); (V.C.); (M.B.); (L.N.); (G.P.A.)
- Council for Agricultural Research and Economics—Research Centre for Viticulture and Enology CREA-VE, Via XXVIII Aprile 26, 31015 Conegliano (TV), Italy
| | - Gian Paolo Accotto
- Institute for Sustainable Plant Protection, National Research Council of Italy (IPSP-CNR), Torino, Strada delle Cacce 73, 10135 Torino, Italy; (A.M.V.); (V.C.); (M.B.); (L.N.); (G.P.A.)
| | - Luisa Lanfranco
- Department of Life Sciences and Systems Biology, University of Torino, Viale Mattioli 25, 10125 Torino, Italy
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14
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De Francesco A, Simeone M, Gómez C, Costa N, García ML. Transgenic Sweet Orange expressing hairpin CP-mRNA in the interstock confers tolerance to citrus psorosis virus in the non-transgenic scion. Transgenic Res 2020; 29:215-228. [PMID: 31970613 DOI: 10.1007/s11248-020-00191-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 01/13/2020] [Indexed: 10/25/2022]
Abstract
The lack of naturally occurring resistance to citrus psorosis virus (CPsV) necessitates a transgenic approach for the development of CPsV-resistant citrus. To evaluate the feasibility of conferring resistance to a non-transgenic scion, we have assembled citrus plants by grafting combining a non-transgenic Sweet Orange as scion, CPsV-resistant transgenic Sweet Orange lines expressing intron-hairpin (ihp) RNA derived from the viral coat protein (ihpCP) as interstock, and a non-transgenic citrus as rootstock. We demonstrated that ihpCP-transcripts translocate through the graft from interstock to scion, triggering the silencing of coat protein mRNA target. Two independent CPsV challenge assays showed that expression of ihpCP in the interstock provides resistance against CPsV in the interstock, and different levels of protection in the non-tg scion, depending of the virus delivery site. These results indicated that grafting is a promising biotechnological alternative to protect woody plants against virus infections in vegetative propagated plants.
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Affiliation(s)
- A De Francesco
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata, CONICET - UNLP, calles 47 y 115 (1900), La Plata, Buenos Aires, Argentina.,Department of Microbiology and Plant Pathology, University of California, Riverside, CA, 92521, USA
| | - M Simeone
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata, CONICET - UNLP, calles 47 y 115 (1900), La Plata, Buenos Aires, Argentina
| | - C Gómez
- Estación Experimental Agropecuaria, INTA Concordia, Ruta Provincial 22 y vías del Ferrocarril (3200), Concordia, Entre Ríos, Argentina
| | - N Costa
- Estación Experimental Agropecuaria, INTA Concordia, Ruta Provincial 22 y vías del Ferrocarril (3200), Concordia, Entre Ríos, Argentina
| | - M L García
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata, CONICET - UNLP, calles 47 y 115 (1900), La Plata, Buenos Aires, Argentina.
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15
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Medzihradszky A, Gyula P, Sós‐Hegedűs A, Szittya G, Burgyán J. Transcriptome reprogramming in the shoot apical meristem of CymRSV-infected Nicotiana benthamiana plants associates with viral exclusion and the lack of recovery. MOLECULAR PLANT PATHOLOGY 2019; 20:1748-1758. [PMID: 31560831 PMCID: PMC6859499 DOI: 10.1111/mpp.12875] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In some plant-virus interactions plants show a sign of healing from virus infection, a phenomenon called symptom recovery. It is assumed that the meristem exclusion of the virus is essential to this process. The discovery of RNA silencing provided a possible mechanism to explain meristem exclusion and recovery. Here we show evidence that silencing is not the reason for meristem exclusion in Nicotiana benthamiana plants infected with Cymbidium ringspot virus (CymRSV). Transcriptome analysis followed by in situ hybridization shed light on the changes in gene expression in the shoot apical meristem (SAM) on virus infection. We observed the down-regulation of meristem-specific genes, including WUSCHEL (WUS). However, WUS was not down-regulated in the SAM of plants infected with meristem-invading viruses such as turnip vein-clearing virus (TVCV) and cucumber mosaic virus (CMV). Moreover, there is no connection between loss of meristem function and fast shoot necrosis since TVCV necrotized the shoot while CMV did not. Our findings suggest that the observed transcriptional changes on virus infection in the shoot are key factors in tip necrosis and symptom recovery. We observed a lack of GLYCERALDEHYDE 3-PHOSPHATE DEHYDROGENASE (GAPDH) expression in tissues around the meristem, which likely stops virus replication and spread into the meristem.
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Affiliation(s)
- Anna Medzihradszky
- Department of Plant BiotechnologyNational Agricultural Research and Innovation CentreSzent‐Györgyi Albert u. 4Gödöllő2100Hungary
| | - Péter Gyula
- Department of Plant BiotechnologyNational Agricultural Research and Innovation CentreSzent‐Györgyi Albert u. 4Gödöllő2100Hungary
| | - Anita Sós‐Hegedűs
- Department of Plant BiotechnologyNational Agricultural Research and Innovation CentreSzent‐Györgyi Albert u. 4Gödöllő2100Hungary
| | - György Szittya
- Department of Plant BiotechnologyNational Agricultural Research and Innovation CentreSzent‐Györgyi Albert u. 4Gödöllő2100Hungary
| | - József Burgyán
- Department of Plant BiotechnologyNational Agricultural Research and Innovation CentreSzent‐Györgyi Albert u. 4Gödöllő2100Hungary
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16
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Walsh H, Vanderschuren H, Taylor S, Rey M. RNA silencing of South African cassava mosaic virus in transgenic cassava expressing AC1/AC4 hp- RNA induces tolerance. BIOTECHNOLOGY REPORTS (AMSTERDAM, NETHERLANDS) 2019; 24:e00383. [PMID: 31763196 PMCID: PMC6864324 DOI: 10.1016/j.btre.2019.e00383] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/13/2019] [Accepted: 10/02/2019] [Indexed: 11/29/2022]
Abstract
Cassava mosaic disease (CMD), caused by geminiviruses, is a major hurdle to cassava production. Due to the heterozygous nature of cassava, breeding for virus resistance is difficult, but cassava has been shown to be a good candidate for genetic engineering using RNA interference (RNAi). T This study reports on the ability of a transgene-derived RNA hairpin, homologous to an overlapping region of the SACMV replication associated protein and putative virus suppressor of silencing protein (AC1/AC4), to confer tolerance in the CMD-susceptible model cassava cultivar 60444. Three of the fourteen transgenic lines expressing SACMV AC1/AC4 hairpin-derived siRNAs showed decreased symptoms and viral loads compared to untransformed control plants. Expression of SACMV AC1/AC4 homologous siRNAs showed that this tolerance is most likely associated with post-transcriptional gene silencing of the virus. This is the first report of targeting the overlapping AC1 and AC4 genes of SACMV conferring CMD tolerance in cassava.
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Affiliation(s)
- H.A. Walsh
- School of Molecular and Cell Biology, University of the Witwatersrand, 1 Jan Smuts Ave, Johannesburg, South Africa
| | - H. Vanderschuren
- Plant Genetics Laboratory, TERRA Teaching and Research Unit, University of Liège, Gembloux Agro-Bio Tech, Belgium
| | - S. Taylor
- School of Molecular and Cell Biology, University of the Witwatersrand, 1 Jan Smuts Ave, Johannesburg, South Africa
| | - M.E.C. Rey
- School of Molecular and Cell Biology, University of the Witwatersrand, 1 Jan Smuts Ave, Johannesburg, South Africa
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17
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Paudel DB, Sanfaçon H. Exploring the Diversity of Mechanisms Associated With Plant Tolerance to Virus Infection. FRONTIERS IN PLANT SCIENCE 2018; 9:1575. [PMID: 30450108 PMCID: PMC6224807 DOI: 10.3389/fpls.2018.01575] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/09/2018] [Indexed: 05/17/2023]
Abstract
Tolerance is defined as an interaction in which viruses accumulate to some degree without causing significant loss of vigor or fitness to their hosts. Tolerance can be described as a stable equilibrium between the virus and its host, an interaction in which each partner not only accommodate trade-offs for survival but also receive some benefits (e.g., protection of the plant against super-infection by virulent viruses; virus invasion of meristem tissues allowing vertical transmission). This equilibrium, which would be associated with little selective pressure for the emergence of severe viral strains, is common in wild ecosystems and has important implications for the management of viral diseases in the field. Plant viruses are obligatory intracellular parasites that divert the host cellular machinery to complete their infection cycle. Highjacking/modification of plant factors can affect plant vigor and fitness. In addition, the toxic effects of viral proteins and the deployment of plant defense responses contribute to the induction of symptoms ranging in severity from tissue discoloration to malformation or tissue necrosis. The impact of viral infection is also influenced by the virulence of the specific virus strain (or strains for mixed infections), the host genotype and environmental conditions. Although plant resistance mechanisms that restrict virus accumulation or movement have received much attention, molecular mechanisms associated with tolerance are less well-understood. We review the experimental evidence that supports the concept that tolerance can be achieved by reaching the proper balance between plant defense responses and virus counter-defenses. We also discuss plant translation repression mechanisms, plant protein degradation or modification pathways and viral self-attenuation strategies that regulate the accumulation or activity of viral proteins to mitigate their impact on the host. Finally, we discuss current progress and future opportunities toward the application of various tolerance mechanisms in the field.
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Affiliation(s)
- Dinesh Babu Paudel
- Department of Botany, The University of British Columbia, Vancouver, BC, Canada
| | - Hélène Sanfaçon
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, BC, Canada
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18
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Paudel DB, Ghoshal B, Jossey S, Ludman M, Fatyol K, Sanfaçon H. Expression and antiviral function of ARGONAUTE 2 in Nicotiana benthamiana plants infected with two isolates of tomato ringspot virus with varying degrees of virulence. Virology 2018; 524:127-139. [PMID: 30195250 DOI: 10.1016/j.virol.2018.08.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 08/16/2018] [Accepted: 08/19/2018] [Indexed: 11/23/2022]
Abstract
ARGONAUTEs (notably AGO1 and AGO2) are effectors of plant antiviral RNA silencing. AGO1 was shown to be required for the temperature-dependent symptom recovery of Nicotiana benthamiana plants infected with tomato ringspot virus (isolate ToRSV-Rasp1) at 27 °C. In this study, we show that symptom recovery from isolate ToRSV-GYV shares similar hallmarks of antiviral RNA silencing but occurs at a wider range of temperatures (21-27 °C). At 21 °C, an early spike in AGO2 mRNAs accumulation was observed in plants infected with either ToRSV-Rasp1 or ToRSV-GYV but the AGO2 protein was only consistently detected in ToRSV-GYV infected plants. Symptom recovery from ToRSV-GYV at 21 °C was not prevented in an ago2 mutant or by silencing of AGO1 or AGO2. We conclude that other factors (possibly other AGOs) contribute to symptom recovery under these conditions. The results also highlight distinct expression patterns of AGO2 in response to ToRSV isolates and environmental conditions.
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Affiliation(s)
- Dinesh Babu Paudel
- Dept of Botany, University of British Columbia, 3529-6270 University Blvd, Vancouver, BC, Canada V6T 1Z4
| | - Basudev Ghoshal
- Dept of Botany, University of British Columbia, 3529-6270 University Blvd, Vancouver, BC, Canada V6T 1Z4
| | - Sushma Jossey
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, PO Box 5000, 4200 Highway 97, Summerland, BC, Canada V0H 1Z0
| | - Marta Ludman
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Center, Szent-Györgyi Albert u. 4, Gödöllő 2100, Hungary
| | - Karoly Fatyol
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Center, Szent-Györgyi Albert u. 4, Gödöllő 2100, Hungary
| | - Hélène Sanfaçon
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, PO Box 5000, 4200 Highway 97, Summerland, BC, Canada V0H 1Z0.
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19
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Basu S, Kumar Kushwaha N, Kumar Singh A, Pankaj Sahu P, Vinoth Kumar R, Chakraborty S. Dynamics of a geminivirus-encoded pre-coat protein and host RNA-dependent RNA polymerase 1 in regulating symptom recovery in tobacco. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2085-2102. [PMID: 29432546 PMCID: PMC6019014 DOI: 10.1093/jxb/ery043] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 01/24/2018] [Indexed: 05/21/2023]
Abstract
RNA silencing is an integral part of the cellular defense mechanisms in plants that act against virus infection. However, the specific role of RNA silencing and the interplay between host and virus components during recovery from geminivirus infection remains unknown. Hence, in this study we aimed to examine the mechanism behind the host-specific recovery of Nicotiana tabacum infected with Tomato leaf curl Gujarat virus (ToLCGV). Unlike Tomato leaf curl New Delhi virus (ToLCNDV), ToLCGV infection resulted in symptom remission in N. tabacum, and we found that this was mainly due to cross-talk between the pre-coat protein (encoded by the AV2 ORF) of the virus and the host RNA-silencing component RNA-dependent RNA polymerase 1 (encoded by NtRDR1) of N. tabacum. Moreover, apart from the AV2 mutant, other mutants of ToLCNDV developed severe symptoms on a transgenic NtRDR1-overexpression line of N. benthamiana. In contrast, inoculation with ToLCGV resulted in symptom remission, which was due to enhanced methylation of the ToLCGV promoter. Our study reveals a novel 'arms race' in which the pre-coat protein of ToLCNDV selectively blocks the recovery process through inhibiting host-specific RDR1-mediated antiviral silencing in tobacco.
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Affiliation(s)
- Saumik Basu
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Nirbhay Kumar Kushwaha
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Ashish Kumar Singh
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Pranav Pankaj Sahu
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - R Vinoth Kumar
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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20
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Martin IR, Vigne E, Berthold F, Komar V, Lemaire O, Fuchs M, Schmitt‐Keichinger C. The 50 distal amino acids of the 2A HP homing protein of Grapevine fanleaf virus elicit a hypersensitive reaction on Nicotiana occidentalis. MOLECULAR PLANT PATHOLOGY 2018; 19:731-743. [PMID: 28387986 PMCID: PMC6637978 DOI: 10.1111/mpp.12558] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/30/2017] [Accepted: 03/31/2017] [Indexed: 06/02/2023]
Abstract
Avirulence factors are critical for the arm's race between a virus and its host in determining incompatible reactions. The response of plants to viruses from the genus Nepovirus in the family Secoviridae, including Grapevine fanleaf virus (GFLV), is well characterized, although the nature and characteristics of the viral avirulence factor remain elusive. By using infectious clones of GFLV strains F13 and GHu in a reverse genetics approach with wild-type, assortant and chimeric viruses, the determinant of necrotic lesions caused by GFLV-F13 on inoculated leaves of Nicotiana occidentalis was mapped to the RNA2-encoded protein 2AHP , particularly to its 50 C-terminal amino acids. The necrotic response showed hallmark characteristics of a genuine hypersensitive reaction, such as the accumulation of phytoalexins, reactive oxygen species, pathogenesis-related protein 1c and hypersensitivity-related (hsr) 203J transcripts. Transient expression of the GFLV-F13 protein 2AHP fused to an enhanced green fluorescent protein (EGFP) tag in N. occidentalis by agroinfiltration was sufficient to elicit a hypersensitive reaction. In addition, the GFLV-F13 avirulence factor, when introduced in GFLV-GHu, which causes a compatible reaction on N. occidentalis, elicited necrosis and partially restricted the virus. This is the first identification of a nepovirus avirulence factor that is responsible for a hypersensitive reaction in both the context of virus infection and transient expression.
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Affiliation(s)
| | - Emmanuelle Vigne
- Université de Strasbourg, INRA, SVQV UMR‐A 1131Colmar68000France
| | - François Berthold
- Université de Strasbourg, CNRS, IBMP UPR 2357Strasbourg67000France
- Present address:
Université de StrasbourgINRA, SVQV UMR‐A 1131Colmar68000France
| | - Véronique Komar
- Université de Strasbourg, INRA, SVQV UMR‐A 1131Colmar68000France
| | - Olivier Lemaire
- Université de Strasbourg, INRA, SVQV UMR‐A 1131Colmar68000France
| | - Marc Fuchs
- Department of Plant Pathology and Plant–Microbe BiologyCornell University, New York State Agricultural Experiment StationGenevaNY14456USA
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21
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Kyallo M, Ateka EM, Sseruwagi P, Ascencio-Ibáñez JT, Ssemakula MO, Skilton R, Ndunguru J. Infectivity of Deinbollia mosaic virus, a novel weed-infecting begomovirus in East Africa. Arch Virol 2017; 162:3439-3445. [PMID: 28791544 PMCID: PMC5640732 DOI: 10.1007/s00705-017-3495-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 07/09/2017] [Indexed: 11/25/2022]
Abstract
Weed-infecting begomoviruses play an important role in the epidemiology of crop diseases because they can potentially infect crops and contribute to the genetic diversity of crop-infecting begomoviruses. Despite the important epidemiological role that weed-infecting begomoviruses play, they remain insufficiently studied in Africa. Recently, we identified Deinbollia mosaic virus (DMV), a distinct begomovirus found naturally infecting the weed host Deinbollia borbonica (Sapindaceae) in Kenya and Tanzania. In this study, we investigated the capacity of DMV to infect a restricted host range of Solanaceae and Euphorbiaceae species. Biolistic inoculation of Nicotiana benthamiana with concatemeric DNAs resulted in systemic infection associated with yellow mosaic symptoms, while DNA partial dimers caused asymptomatic systemic infection. DMV was not infectious to cassava (Manihot esculenta Crantz), suggesting host resistance to the virus. Here, we demonstrate the first experimental infectivity analysis of DMV in N. benthamiana and cassava.
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Affiliation(s)
- Martina Kyallo
- Biosciences eastern and central Africa-International Livestock Research Institute (BecA-ILRI) Hub, P.O. Box 30709-00100, Nairobi, Kenya.
| | - Elijah Miinda Ateka
- Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200, Nairobi, Kenya
| | - Peter Sseruwagi
- Mikocheni Agricultural Research Institute, P.O. Box 6226, Dar es Salaam, Tanzania
| | - José Trinidad Ascencio-Ibáñez
- Department of Molecular and Structural Biochemistry, North Carolina State University, 132 Polk Hall, Raleigh, NC, 27695, USA
| | | | - Robert Skilton
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Joseph Ndunguru
- Mikocheni Agricultural Research Institute, P.O. Box 6226, Dar es Salaam, Tanzania
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22
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Wosula EN, Tatineni S, Wegulo SN, Hein GL. Effect of Temperature on Wheat Streak Mosaic Disease Development in Winter Wheat. PLANT DISEASE 2017; 101:324-330. [PMID: 30681928 DOI: 10.1094/pdis-07-16-1053-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Temperature is one of the key factors that influence viral disease development in plants. In this study, temperature effect on Wheat streak mosaic virus (WSMV) replication and in planta movement was determined using a green fluorescent protein (GFP)-tagged virus in two winter wheat cultivars. Virus-inoculated plants were first incubated at 10, 15, 20, and 25°C for 21 days, followed by 27°C for 14 days; and, in a second experiment, virus-inoculated plants were initially incubated at 27°C for 3 days, followed by 10, 15, 20, and 25°C for 21 days. In the first experiment, WSMV-GFP in susceptible 'Tomahawk' wheat at 10°C was restricted at the point of inoculation whereas, at 15°C, the virus moved systemically, accompanied with mild symptoms, and, at 20 and 25°C, WSMV elicited severe WSMV symptoms. In resistant 'Mace' wheat (PI 651043), WSMV-GFP was restricted at the point of inoculation at 10 and 15°C but, at 20 and 25°C, the virus infected systemically with no visual symptoms. Some plants that were not systemically infected at low temperatures expressed WSMV-GFP in regrowth shoots when later held at 27°C. In the second experiment, Tomahawk plants (100%) expressed systemic WSMV-GFP after 21 days at all four temperature levels; however, systemic WSMV expression in Mace was delayed at the lower temperatures. These results indicate that temperature played an important role in WSMV replication, movement, and symptom development in resistant and susceptible wheat cultivars. This study also demonstrates that suboptimal temperatures impair WSMV movement but the virus rapidly begins to replicate and spread in planta under optimal temperatures.
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Affiliation(s)
- E N Wosula
- International Institute of Tropical Agriculture, Dar es Salaam, Tanzania
| | - S Tatineni
- United States Department of Agriculture-Agricultural Research Service, and Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln 68583
| | - S N Wegulo
- Department of Plant Pathology, University of Nebraska-Lincoln
| | - G L Hein
- Department of Entomology, University of Nebraska-Lincoln
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23
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Kuria P, Ilyas M, Ateka E, Miano D, Onguso J, Carrington JC, Taylor NJ. Differential response of cassava genotypes to infection by cassava mosaic geminiviruses. Virus Res 2016; 227:69-81. [PMID: 27693919 PMCID: PMC5130204 DOI: 10.1016/j.virusres.2016.09.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/26/2016] [Accepted: 09/29/2016] [Indexed: 12/21/2022]
Abstract
Cassava genotypes respond differently to infection by cassava mosaic geminiviruses. Cassava mosaic disease resistant loci prompt recovery from systemic infection. CMD symptoms are directly correlated with contents of viral DNA and virus specific small RNAs. CMD infected plants abundantly accumulate 21–24 nt of virus specific small RNAs. VsRNAs heterogeneously map the entire virus genome in both polarities.
Mitigation of cassava mosaic disease (CMD) focuses on the introgression of resistance imparted by the polygenic recessive (CMD1), dominant monogenic (CMD2) and CMD3 loci. The mechanism(s) of resistance they impart, however, remain unknown. Two CMD susceptible and nine CMD resistant cassava genotypes were inoculated by microparticle bombardment with infectious clones of African cassava mosaic virus Cameroon strain (ACMV-CM) and the Kenyan strain K201 of East African cassava mosaic virus (EACMV KE2 [K201]). Genotypes carrying the CMD1 (TMS 30572), CMD2 (TME 3, TME 204 and Oko-iyawo) and CMD3 (TMS 97/0505) resistance mechanisms showed high levels of resistance to ACMV-CM, with viral DNA undetectable by PCR beyond 7 days post inoculation (dpi). In contrast, all genotypes initially developed severe CMD symptoms and accumulated high virus titers after inoculation with EACMV KE2 (K201). Resistant genotypes recovered to become asymptomatic by 65 dpi with no detectable virus in newly formed leaves. Genotype TMS 97/2205 showed highest resistance to EACMV KE2 (K201) with <30% of inoculated plants developing symptoms followed by complete recovery by 35 dpi. Deep sequencing of small RNAs confirmed production of 21–24 nt virus derived small RNAs (vsRNA) that mapped to cover the entire ACMV-CM and EACMV KE2 (K201) viral genomes in both polarities, with hotspots seen within gene coding regions. In resistant genotypes, total vsRNAs were most abundant at 20 and 35 dpi but reduced significantly upon recovery from CMD. In contrast, CMD susceptible genotypes displayed abundant vsRNAs throughout the experimental period. The percentage of vsRNAs reads ranked by class size were 21nt (45%), 22 nt (28%) and 24 nt (18%) in all genotypes studied. The number of vsRNA reads directly correlated with virus titer and CMD symptoms.
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Affiliation(s)
- Paul Kuria
- Jomo Kenyatta University of Agriculture and Technology, PO Box 62000-00200 Nairobi, Kenya; Kenya Agricultural and Livestock Research Organization, PO Box 57811-00200, Nairobi, Kenya
| | - Muhammad Ilyas
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO, 63132, USA
| | - Elijah Ateka
- Jomo Kenyatta University of Agriculture and Technology, PO Box 62000-00200 Nairobi, Kenya
| | - Douglas Miano
- University of Nairobi, PO BOX 30197, 00100, Nairobi, Kenya
| | - Justus Onguso
- Jomo Kenyatta University of Agriculture and Technology, PO Box 62000-00200 Nairobi, Kenya
| | - James C Carrington
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO, 63132, USA
| | - Nigel J Taylor
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO, 63132, USA.
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Fuchs M, Schmitt-Keichinger C, Sanfaçon H. A Renaissance in Nepovirus Research Provides New Insights Into Their Molecular Interface With Hosts and Vectors. Adv Virus Res 2016; 97:61-105. [PMID: 28057260 DOI: 10.1016/bs.aivir.2016.08.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Nepoviruses supplied seminal landmarks to the historical trail of plant virology. Among the first agriculturally relevant viruses recognized in the late 1920s and among the first plant viruses officially classified in the early 1970s, nepoviruses also comprise the first species for which a soil-borne ectoparasitic nematode vector was identified. Early research on nepoviruses shed light on the genome structure and expression, biological properties of the two genomic RNAs, and mode of transmission. In recent years, research on nepoviruses enjoyed an extraordinary renaissance. This resurgence provided new insights into the molecular interface between viruses and their plant hosts, and between viruses and dagger nematode vectors to advance our understanding of some of the major steps of the infectious cycle. Here we examine these recent findings, highlight ongoing work, and offer some perspectives for future research.
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Affiliation(s)
- M Fuchs
- Section of Plant Pathology and Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, New York State Agricultural Experiment Station, Geneva, NY, United States.
| | - C Schmitt-Keichinger
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
| | - H Sanfaçon
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, BC, Canada
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Bengyella L, Waikhom SD, Allie F, Rey C. Virus tolerance and recovery from viral induced-symptoms in plants are associated with transcriptome reprograming. PLANT MOLECULAR BIOLOGY 2015; 89:243-52. [PMID: 26358043 DOI: 10.1007/s11103-015-0362-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/08/2015] [Indexed: 05/07/2023]
Abstract
Plant recovery from viral infection is characterized by initial severe systemic symptoms which progressively decrease, leading to reduced symptoms or symptomless leaves at the apices. A key feature to plant recovery from invading nucleic acids such as viruses is the degree of the host's initial basal immunity response. We review current links between RNA silencing, recovery and tolerance, and present a model in which, in addition to regulation of resistance (R) and other defence-related genes by RNA silencing, viral infections incite perturbations of the host physiological state that trigger reprogramming of host responses to by-pass severe symptom development, leading to partial or complete recovery. Recovery, in particular in perennial hosts, may trigger tolerance or virus accommodation. We discuss evidence suggesting that plant viruses can avoid total clearance but persistently replicate at low levels, thereby modulating the host transcriptome response which minimizes fitness cost and triggers recovery from viral-symptoms. In some cases a susceptible host may fail to recover from initial viral systemic symptoms, yet, accommodates the persistent virus throughout the life span, a phenomenon herein referred to as non-recovery accommodation, which differs from tolerance in that there is no distinct recovery phase, and differs from susceptibility in that the host is not killed. Recent advances in plant recovery from virus-induced symptoms involving host transcriptome reprogramming are discussed.
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Affiliation(s)
- Louis Bengyella
- School of Molecular and Cell Biology, University of the Witwatersrand, 1, Jan Smuts 6, Ave, Johannesburg, Braamfontein, 2000, South Africa
| | - Sayanika D Waikhom
- Centre of Advanced Study in Life Sciences, Manipur University, Imphal, Manipur, 795003, India
- School of Basic and Biomedical Science, University of Health and Allied Sciences, PMB 31, Ho, Volta Region, Ghana
| | - Farhahna Allie
- School of Molecular and Cell Biology, University of the Witwatersrand, 1, Jan Smuts 6, Ave, Johannesburg, Braamfontein, 2000, South Africa
| | - Chrissie Rey
- School of Molecular and Cell Biology, University of the Witwatersrand, 1, Jan Smuts 6, Ave, Johannesburg, Braamfontein, 2000, South Africa.
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Symptom recovery in virus-infected plants: Revisiting the role of RNA silencing mechanisms. Virology 2015; 479-480:167-79. [DOI: 10.1016/j.virol.2015.01.008] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/02/2015] [Accepted: 01/08/2015] [Indexed: 01/11/2023]
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Nie X, Molen TA. Host recovery and reduced virus level in the upper leaves after Potato virus Y infection occur in tobacco and tomato but not in potato plants. Viruses 2015; 7:680-98. [PMID: 25679498 PMCID: PMC4353910 DOI: 10.3390/v7020680] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/02/2015] [Indexed: 01/12/2023] Open
Abstract
In this study, the recovery phenomenon following infection with Potato virus Y (PVY) was investigated in tobacco (Nicotiana tobaccum), tomato (Solanum lycopersicum) and potato (Solanum tuberosum) plants. In tobacco plants, infection of severe strains of PVY (PVYN or PVYN:O) induced conspicuous vein clearing and leaf deformation in the first three leaves above the inoculated leaves, but much milder symptoms in the upper leaves. The recovery phenotype was not obvious in tobacco plants infected with PVY strain that induce mild symptoms (PVYO). However, regardless of the virus strains, reduction in PVY RNA levels was similarly observed in the upper leaves of these plants. Removal of the first three leaves above the inoculated leaves interfered with the occurrence of recovery, suggesting that the signal(s) mediating the recovery is likely generated in these leaves. In PVYN or PVYN:O but not in PVYO-infected tobacco plants, the expression of PR-1a transcripts were correlated with the accumulation level of PVY RNA. Reduced level of PVY RNA in the upper leaves was also observed in infected tomato plants, whereas such phenomenon was not observed in potato plants. PVY-derived small RNAs were detected in both tobacco and potato plants and their accumulation levels were correlated with PVY RNA levels. Our results demonstrate that the recovery phenotype following PVY infection is host-specific and not necessarily associated with the expression of PR-1a and generation of PVY small RNAs.
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Affiliation(s)
- Xianzhou Nie
- Potato Research Centre, Agriculture and Agri-Food Canada, P.O. Box 20280, 850 Lincoln Road, Fredericton, NB E3B 4Z7, Canada.
| | - Teresa A Molen
- Potato Research Centre, Agriculture and Agri-Food Canada, P.O. Box 20280, 850 Lincoln Road, Fredericton, NB E3B 4Z7, Canada.
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Ma X, Nicole MC, Meteignier LV, Hong N, Wang G, Moffett P. Different roles for RNA silencing and RNA processing components in virus recovery and virus-induced gene silencing in plants. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:919-32. [PMID: 25385769 DOI: 10.1093/jxb/eru447] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A major antiviral mechanism in plants is mediated by RNA silencing, which relies on the cleavage of viral dsRNA into virus-derived small interfering RNAs (vsiRNAs) by DICER-like enzymes. Members of the Argonaute (AGO) family of endonucleases then use these vsiRNA as guides to target viral RNA. This can result in a phenomenon known as recovery, whereby the plant silences viral gene expression and recovers from viral symptoms. Endogenous mRNAs can also be targeted by vsiRNAs in a phenomenon known as virus-induced gene silencing (VIGS). Although related to other RNA silencing mechanisms, it has not been established if recovery and VIGS are mediated by the same molecular mechanisms. We used tobacco rattle virus (TRV) carrying a fragment of the phytoene desaturase (PDS) gene (TRV-PDS) or expressing green fluorescent protein (TRV-GFP) as readouts for VIGS and recovery, respectively, in Arabidopsis ago mutants. Our results demonstrated roles for AGO2 and AGO4 in susceptibility to TRV, whereas VIGS of endogenous genes appeared to be largely mediated by AGO1. However, recovery appeared to be mediated by different components, as all the aforementioned mutants were able to recover from TRV-GFP inoculation. TRV RNAs from recovered plants associated less with ribosomes, suggesting that recovery involves translational repression of viral transcripts. Translationally repressed RNAs often accumulate in RNA processing bodies (PBs), where they are eventually processed by decapping enzymes. Consistent with this, we found that viral recovery induced increased PB formation and that a decapping mutant (DCP2) showed increased VIGS and virus RNA accumulation, indicating an important role for PBs in eliminating viral RNA.
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Affiliation(s)
- Xiaofang Ma
- State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, PR China College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China Université de Sherbrooke, Département de Biologie, 2500 Boulevard de l'Université, Sherbrooke J1K 2R1, QC, Canada
| | - Marie-Claude Nicole
- Université de Sherbrooke, Département de Biologie, 2500 Boulevard de l'Université, Sherbrooke J1K 2R1, QC, Canada
| | - Louis-Valentin Meteignier
- Université de Sherbrooke, Département de Biologie, 2500 Boulevard de l'Université, Sherbrooke J1K 2R1, QC, Canada
| | - Ni Hong
- State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, PR China College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Guoping Wang
- State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, PR China College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Peter Moffett
- Université de Sherbrooke, Département de Biologie, 2500 Boulevard de l'Université, Sherbrooke J1K 2R1, QC, Canada
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Rossi M, Vallino M, Abbà S, Ciuffo M, Balestrini R, Genre A, Turina M. The Importance of the KR-Rich Region of the Coat Protein of Ourmia melon virus for Host Specificity, Tissue Tropism, and Interference With Antiviral Defense. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:30-41. [PMID: 25494356 DOI: 10.1094/mpmi-07-14-0197-r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The N-terminal region of the Ourmia melon virus (OuMV) coat protein (CP) contains a short lysine/arginine-rich (KR) region. By alanine scanning mutagenesis, we showed that the KR region influences pathogenicity and virulence of OuMV without altering viral particle assembly. A mutant, called OuMV6710, with three basic residue substitutions in the KR region, was impaired in the ability to maintain the initial systemic infection in Nicotiana benthamiana and to infect both cucumber and melon plants systemically. The integrity of this protein region was also crucial for encapsidation of viral genomic RNA; in fact, certain mutations within the KR region partially compromised the RNA encapsidation efficiency of the CP. In Arabidopsis thaliana Col-0, OuMV6710 was impaired in particle accumulation; however, this phenotype was abolished in dcl2/dcl4 and dcl2/dcl3/dcl4 Arabidopsis mutants defective for antiviral silencing. Moreover, in contrast to CPwt, in situ immunolocalization experiments indicated that CP6710 accumulates efficiently in the spongy mesophyll tissue of infected N. benthamiana and A. thaliana leaves but only occasionally infects palisade tissues. These results provided strong evidence of a crucial role for OuMV CP during viral infection and highlighted the relevance of the KR region in determining tissue tropism, host range, pathogenicity, and RNA affinity, which may be all correlated with a possible CP silencing-suppression activity.
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Karran RA, Sanfaçon H. Tomato ringspot virus coat protein binds to ARGONAUTE 1 and suppresses the translation repression of a reporter gene. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:933-43. [PMID: 24804809 DOI: 10.1094/mpmi-04-14-0099-r] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
RNA silencing regulates plant gene expression and antiviral defenses and functions by cleaving target RNAs or repressing translation. As a counter defense, many plant viruses encode suppressor proteins that sequester small RNAs or inactivate Argonaute (AGO) proteins. All known plant virus silencing suppressor activities eventually inhibit the degradation of target mRNAs. Using a transiently expressed green fluorescent protein (GFP) reporter gene, we show that Tomato ringspot virus (ToRSV) coat protein (CP) is a suppressor of RNA silencing that enhances GFP expression but does not prevent the degradation of the GFP mRNA or the accumulation of GFP small interfering RNAs (siRNAs). Coexpression of the CP with GFP resulted in increased association of residual GFP mRNAs with polysome fractions and reduced association of GFP siRNAs with monosome fractions. AGO1 was co-immunoprecipitated with the CP and CP expression destabilized AGO1. A WG motif within the CP was critical for the enhanced GFP expression, AGO1 interaction, and AGO1 destabilization, suggesting that the ToRSV CP acts as an AGO-hook protein and competes for AGO binding with a plant cellular GW/WG protein involved in translation repression.
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Gottula J, Lewis R, Saito S, Fuchs M. Allopolyploidy and the evolution of plant virus resistance. BMC Evol Biol 2014; 14:149. [PMID: 24992820 PMCID: PMC4226957 DOI: 10.1186/1471-2148-14-149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 06/25/2014] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The relationship between allopolyploidy and plant virus resistance is poorly understood. To determine the relationship of plant evolutionary history and basal virus resistance, a panel of Nicotiana species from diverse geographic regions and ploidy levels was assessed for resistance to non-coevolved viruses from the genus Nepovirus, family Secoviridae. The heritability of resistance was tested in a panel of synthetic allopolyploids. Leaves of different positions on each inoculated plant were tested for virus presence and a subset of plants was re-inoculated and assessed for systemic recovery. RESULTS Depending on the host-virus combination, plants displayed immunity, susceptibility or intermediate levels of resistance. Synthetic allopolyploids showed an incompletely dominant resistance phenotype and manifested systemic recovery. Plant ploidy was weakly negatively correlated with virus resistance in Nicotiana species, but this trend did not hold when synthetic allopolyploids were taken into account. Furthermore, a relationship between resistance and geographical origin was observed. CONCLUSION The gradients of resistance and virulence corresponded to a modified matching allele model of resistance. Intermediate resistance responses of allopolyploids corresponded with a model of multi-allelic additive resistance. The variable virus resistance of extant allopolyploids suggested that selection-based mechanisms surpass ploidy with respect to evolution of basal resistance to viruses.
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Affiliation(s)
- John Gottula
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA
| | - Ramsey Lewis
- Department of Crop Science, North Carolina State University, 4310 Williams Hall Campus, Box 7620, Raleigh, NC 27695-7620, USA
| | - Seiya Saito
- Kearney Agricultural Research Center, University of California, Parlier, CA 93648, USA
| | - Marc Fuchs
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA
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Santovito E, Mascia T, Siddiqui SA, Minutillo SA, Valkonen JPT, Gallitelli D. Infection cycle of Artichoke Italian latent virus in tobacco plants: meristem invasion and recovery from disease symptoms. PLoS One 2014; 9:e99446. [PMID: 24911029 PMCID: PMC4050035 DOI: 10.1371/journal.pone.0099446] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 05/14/2014] [Indexed: 11/18/2022] Open
Abstract
Nepoviral infections induce recovery in fully expanded leaves but persist in shoot apical meristem (SAM) by a largely unknown mechanism. The dynamics of infection of a grapevine isolate of Artichoke Italian latent virus (AILV-V, genus Nepovirus) in tobacco plants, including colonization of SAM, symptom induction and subsequent recovery of mature leaves from symptoms, were characterized. AILV-V moved from the inoculated leaves systemically and invaded SAM in 7 days post-inoculation (dpi), remaining detectable in SAM at least up to 40 dpi. The new top leaves recovered from viral symptoms earliest at 21 dpi. Accumulation of viral RNA to a threshold level was required to trigger the overexpression of RDR6 and DCL4. Consequently, accumulation of viral RNA decreased in the systemically infected leaves, reaching the lowest concentration in the 3rd and 4th leaves at 23 dpi, which was concomitant with recovery of the younger, upper leaves from disease symptoms. No evidence of virus replication was found in the recovered leaves, but they contained infectious virus particles and were protected against re-inoculation with AILV-V. In this study we also showed that AILV-V did not suppress initiation or maintenance of RNA silencing in transgenic plants, but was able to interfere with the cell-to-cell movement of the RNA silencing signal. Our results suggest that AILV-V entrance in SAM and activation of RNA silencing may be distinct processes since the latter is triggered in fully expanded leaves by the accumulation of viral RNA above a threshold level rather than by virus entrance in SAM.
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Affiliation(s)
- Elisa Santovito
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Tiziana Mascia
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, Bari, Italy
- Istituto di Virologia vegetale del Consiglio Nazionale della Ricerca, Unità Operativa di Supporto di Bari, Bari, Italy
| | - Shahid A. Siddiqui
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| | - Serena Anna Minutillo
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Jari P. T. Valkonen
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| | - Donato Gallitelli
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari Aldo Moro, Bari, Italy
- Istituto di Virologia vegetale del Consiglio Nazionale della Ricerca, Unità Operativa di Supporto di Bari, Bari, Italy
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Margaria P, Bosco L, Vallino M, Ciuffo M, Mautino GC, Tavella L, Turina M. The NSs protein of tomato spotted wilt virus is required for persistent infection and transmission by Frankliniella occidentalis. J Virol 2014; 88:5788-802. [PMID: 24623427 PMCID: PMC4019118 DOI: 10.1128/jvi.00079-14] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 03/04/2014] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Tomato spotted wilt virus (TSWV) is the type member of tospoviruses (genus Tospovirus), plant-infecting viruses that cause severe damage to ornamental and vegetable crops. Tospoviruses are transmitted by thrips in the circulative propagative mode. We generated a collection of NSs-defective TSWV isolates and showed that TSWV coding for truncated NSs protein could not be transmitted by Frankliniella occidentalis. Quantitative reverse transcription (RT)-PCR and immunostaining of individual insects detected the mutant virus in second-instar larvae and adult insects, demonstrating that insects could acquire and accumulate the NSs-defective virus. Nevertheless, adults carried a significantly lower viral load, resulting in the absence of transmission. Genome sequencing and analyses of reassortant isolates showed genetic evidence of the association between the loss of competence in transmission and the mutation in the NSs coding sequence. Our findings offer new insight into the TSWV-thrips interaction and Tospovirus pathogenesis and highlight, for the first time in the Bunyaviridae family, a major role for the S segment, and specifically for the NSs protein, in virulence and efficient infection in insect vector individuals. IMPORTANCE Our work is the first to show a role for the NSs protein in virus accumulation in the insect vector in the Bunyaviridae family: demonstration was obtained for the system TSWV-F. occidentalis, arguably one of the most damaging combination for vegetable crops. Genetic evidence of the involvement of the NSs protein in vector transmission was provided with multiple approaches.
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Affiliation(s)
- P. Margaria
- Istituto di Virologia Vegetale, Sez. di Torino, CNR, Turin, Italy
| | - L. Bosco
- Dipartimento di Scienze Agrarie, Forestali e Alimentari (DISAFA), University of Turin, Grugliasco (TO), Italy
| | - M. Vallino
- Istituto di Virologia Vegetale, Sez. di Torino, CNR, Turin, Italy
| | - M. Ciuffo
- Istituto di Virologia Vegetale, Sez. di Torino, CNR, Turin, Italy
| | - G. C. Mautino
- Dipartimento di Scienze Agrarie, Forestali e Alimentari (DISAFA), University of Turin, Grugliasco (TO), Italy
| | - L. Tavella
- Dipartimento di Scienze Agrarie, Forestali e Alimentari (DISAFA), University of Turin, Grugliasco (TO), Italy
| | - M. Turina
- Istituto di Virologia Vegetale, Sez. di Torino, CNR, Turin, Italy
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Ghoshal B, Sanfaçon H. Temperature-dependent symptom recovery in Nicotiana benthamiana plants infected with tomato ringspot virus is associated with reduced translation of viral RNA2 and requires ARGONAUTE 1. Virology 2014; 456-457:188-97. [PMID: 24889238 DOI: 10.1016/j.virol.2014.03.026] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/27/2014] [Accepted: 03/23/2014] [Indexed: 12/22/2022]
Abstract
Symptom recovery in nepovirus-infected plants has been attributed to the induction of RNA silencing. However, recovery is not always accompanied with viral RNA clearance. In this study, we show that recovery of Nicotiana benthamiana plants infected with the tomato ringspot virus (ToRSV) is associated with a reduction of the steady-state levels of RNA2-encoded coat protein (CP) and movement protein but not of RNA2. In vivo labeling experiments revealed efficient synthesis of the CP early in infection, but reduced RNA2 translation later in infection. Silencing of Argonaute1-like (Ago1) genes prevented both symptom recovery and RNA2 translation repression. Similarly, growing the plants at lower temperature (21 °C rather than 27 °C) alleviated the recovery and the translation repression. Taken together, our results suggest that recovery of ToRSV-infected plants is associated with an Ago1-dependent mechanism that represses the translation of viral RNA2.
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Affiliation(s)
- Basudev Ghoshal
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Hélène Sanfaçon
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4; Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, PO Box 5000, 4200 Highway 97, Summerland, BC, Canada V0H 1Z0.
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Vigne E, Gottula J, Schmitt-Keichinger C, Komar V, Ackerer L, Belval L, Rakotomalala L, Lemaire O, Ritzenthaler C, Fuchs M. A strain-specific segment of the RNA-dependent RNA polymerase of grapevine fanleaf virus determines symptoms in Nicotiana species. J Gen Virol 2013; 94:2803-2813. [PMID: 24088345 DOI: 10.1099/vir.0.057646-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Factors involved in symptom expression of viruses from the genus Nepovirus in the family Secoviridae such as grapevine fanleaf virus (GFLV) are poorly characterized. To identify symptom determinants encoded by GFLV, infectious cDNA clones of RNA1 and RNA2 of strain GHu were developed and used alongside existing infectious cDNA clones of strain F13 in a reverse genetics approach. In vitro transcripts of homologous combinations of RNA1 and RNA2 induced systemic infection in Nicotiana benthamiana and Nicotiana clevelandii with identical phenotypes to WT virus strains, i.e. vein clearing and chlorotic spots on N. benthamiana and N. clevelandii for GHu, respectively, and lack of symptoms on both hosts for F13. The use of assorted transcripts mapped symptom determinants on RNA1 of GFLV strain GHu, in particular within the distal 408 nt of the RNA-dependent RNA polymerase (1E(Pol)), as shown by RNA1 transcripts for which coding regions or fragments derived thereof were swapped. Semi-quantitative analyses indicated no significant differences in virus titre between symptomatic and asymptomatic plants infected with various recombinants. Also, unlike the nepovirus tomato ringspot virus, no apparent proteolytic cleavage of GFLV protein 1E(Pol) was detected upon virus infection or transient expression in N. benthamiana. In addition, GFLV protein 1E(Pol) failed to suppress silencing of EGFP in transgenic N. benthamiana expressing EGFP or to enhance GFP expression in patch assays in WT N. benthamiana. Together, our results suggest the existence of strain-specific functional domains, including a symptom determinant module, on the RNA-dependent RNA polymerase of GFLV.
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Affiliation(s)
- Emmanuelle Vigne
- Université de Strasbourg, UMR 1131 'Santé de la Vigne et Qualité du Vin', 68021 Colmar, France
- INRA, UMR 1131 'Santé de la Vigne et Qualité du Vin', 68021 Colmar, France
| | - John Gottula
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA
| | - Corinne Schmitt-Keichinger
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France
| | - Véronique Komar
- Université de Strasbourg, UMR 1131 'Santé de la Vigne et Qualité du Vin', 68021 Colmar, France
- INRA, UMR 1131 'Santé de la Vigne et Qualité du Vin', 68021 Colmar, France
| | - Léa Ackerer
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France
| | - Lorène Belval
- Université de Strasbourg, UMR 1131 'Santé de la Vigne et Qualité du Vin', 68021 Colmar, France
- INRA, UMR 1131 'Santé de la Vigne et Qualité du Vin', 68021 Colmar, France
| | - Lalaina Rakotomalala
- Université de Strasbourg, UMR 1131 'Santé de la Vigne et Qualité du Vin', 68021 Colmar, France
- INRA, UMR 1131 'Santé de la Vigne et Qualité du Vin', 68021 Colmar, France
| | - Olivier Lemaire
- Université de Strasbourg, UMR 1131 'Santé de la Vigne et Qualité du Vin', 68021 Colmar, France
- INRA, UMR 1131 'Santé de la Vigne et Qualité du Vin', 68021 Colmar, France
| | - Christophe Ritzenthaler
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France
| | - Marc Fuchs
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA
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Bhat S, Folimonova SY, Cole AB, Ballard KD, Lei Z, Watson BS, Sumner LW, Nelson RS. Influence of host chloroplast proteins on Tobacco mosaic virus accumulation and intercellular movement. PLANT PHYSIOLOGY 2013; 161:134-47. [PMID: 23096159 PMCID: PMC3532247 DOI: 10.1104/pp.112.207860] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 10/22/2012] [Indexed: 05/18/2023]
Abstract
Tobacco mosaic virus (TMV) forms dense cytoplasmic bodies containing replication-associated proteins (virus replication complexes [VRCs]) upon infection. To identify host proteins that interact with individual viral components of VRCs or VRCs in toto, we isolated viral replicase- and VRC-enriched fractions from TMV-infected Nicotiana tabacum plants. Two host proteins in enriched fractions, ATP-synthase γ-subunit (AtpC) and Rubisco activase (RCA) were identified by matrix-assisted laser-desorption ionization time-of-flight mass spectrometry or liquid chromatography-tandem mass spectrometry. Through pull-down analysis, RCA bound predominantly to the region between the methyltransferase and helicase domains of the TMV replicase. Tobamovirus, but not Cucumber mosaic virus or Potato virus X, infection of N. tabacum plants resulted in 50% reductions in Rca and AtpC messenger RNA levels. To investigate the role of these host proteins in TMV accumulation and plant defense, we used a Tobacco rattle virus vector to silence these genes in Nicotiana benthamiana plants prior to challenge with TMV expressing green fluorescent protein. TMV-induced fluorescent lesions on Rca- or AtpC-silenced leaves were, respectively, similar or twice the size of those on leaves expressing these genes. Silencing Rca and AtpC did not influence the spread of Tomato bushy stunt virus and Potato virus X. In AtpC- and Rca-silenced leaves TMV accumulation and pathogenicity were greatly enhanced, suggesting a role of both host-encoded proteins in a defense response against TMV. In addition, silencing these host genes altered the phenotype of the TMV infection foci and VRCs, yielding foci with concentric fluorescent rings and dramatically more but smaller VRCs. The concentric rings occurred through renewed virus accumulation internal to the infection front.
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Affiliation(s)
- Sumana Bhat
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma 73401
| | | | | | - Kimberly D. Ballard
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma 73401
| | - Zhentian Lei
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma 73401
| | - Bonnie S. Watson
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma 73401
| | - Lloyd W. Sumner
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma 73401
| | - Richard S. Nelson
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma 73401
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Abstract
Ilarviruses were among the first 16 groups of plant viruses approved by ICTV. Like Alfalfa mosaic virus (AMV), bromoviruses, and cucumoviruses they are isometric viruses and possess a single-stranded, tripartite RNA genome. However, unlike these other three groups, ilarviruses were recognized as being recalcitrant subjects for research (their ready lability is reflected in the sigla used to create the group name) and were renowned as unpromising subjects for the production of antisera. However, it was recognized that they shared properties with AMV when the phenomenon of genome activation, in which the coat protein (CP) of the virus is required to be present to initiate infection, was demonstrated to cross group boundaries. The CP of AMV could activate the genome of an ilarvirus and vice versa. Development of the molecular information for ilarviruses lagged behind the knowledge available for the more extensively studied AMV, bromoviruses, and cucumoviruses. In the past 20 years, genomic data for most known ilarviruses have been developed facilitating their detection and allowing the factors involved in the molecular biology of the genus to be investigated. Much information has been obtained using Prunus necrotic ringspot virus and the more extensively studied AMV. A relationship between some ilarviruses and the cucumoviruses has been defined with the recognition that members of both genera encode a 2b protein involved in RNA silencing and long distance viral movement. Here, we present a review of the current knowledge of both the taxonomy and the molecular biology of this genus of agronomically and horticulturally important viruses.
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Lu J, Du ZX, Kong J, Chen LN, Qiu YH, Li GF, Meng XH, Zhu SF. Transcriptome analysis of Nicotiana tabacum infected by Cucumber mosaic virus during systemic symptom development. PLoS One 2012; 7:e43447. [PMID: 22952684 PMCID: PMC3429483 DOI: 10.1371/journal.pone.0043447] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 07/19/2012] [Indexed: 11/19/2022] Open
Abstract
Virus infection of plants may induce a variety of disease symptoms. However, little is known about the molecular mechanism of systemic symptom development in infected plants. Here we performed the first next-generation sequencing study to identify gene expression changes associated with disease development in tobacco plants (Nicotiana tabacum cv. Xanthi nc) induced by infection with the M strain of Cucumber mosaic virus (M-CMV). Analysis of the tobacco transcriptome by RNA-Seq identified 95,916 unigenes, 34,408 of which were new transcripts by database searches. Deep sequencing was subsequently used to compare the digital gene expression (DGE) profiles of the healthy plants with the infected plants at six sequential disease development stages, including vein clearing, mosaic, severe chlorosis, partial and complete recovery, and secondary mosaic. Thousands of differentially expressed genes were identified, and KEGG pathway analysis of these genes suggested that many biological processes, such as photosynthesis, pigment metabolism and plant-pathogen interaction, were involved in systemic symptom development. Our systematic analysis provides comprehensive transcriptomic information regarding systemic symptom development in virus-infected plants. This information will help further our understanding of the detailed mechanisms of plant responses to viral infection.
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Affiliation(s)
- Jie Lu
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Zhi-Xin Du
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Jun Kong
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Ling-Na Chen
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Yan-Hong Qiu
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Gui-Fen Li
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
| | - Xiao-Hua Meng
- Beijing Genomics Institute-Shenzhen, Shenzhen, China
| | - Shui-Fang Zhu
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing, China
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Andika IB, Kondo H, Nishiguchi M, Tamada T. The cysteine-rich proteins of beet necrotic yellow vein virus and tobacco rattle virus contribute to efficient suppression of silencing in roots. J Gen Virol 2012; 93:1841-1850. [PMID: 22647371 DOI: 10.1099/vir.0.043513-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many plant viruses encode proteins that suppress RNA silencing, but little is known about the activity of silencing suppressors in roots. This study examined differences in the silencing suppression activity of different viruses in leaves and roots of Nicotiana benthamiana plants. Infection by tobacco mosaic virus, potato virus Y and cucumber mosaic virus but not potato virus X (PVX) resulted in strong silencing suppression activity of a transgene in both leaves and roots, whereas infection by beet necrotic yellow vein virus (BNYVV) and tobacco rattle virus (TRV) showed transgene silencing suppression in roots but not in leaves. For most viruses tested, viral negative-strand RNA accumulated at a very low level in roots, compared with considerable levels of positive-strand genomic RNA. Co-inoculation of leaves with PVX and either BNYVV or TRV produced an increase in PVX negative-strand RNA and subgenomic RNA (sgRNA) accumulation in roots. The cysteine-rich proteins (CRPs) BNYVV p14 and TRV 16K showed weak silencing suppression activity in leaves. However, when either of these CRPs was expressed from a PVX vector, there was an enhancement of PVX negative-strand RNA and sgRNA accumulation in roots compared with PVX alone. Such enhancement of PVX sgRNAs was also observed by expression of CRPs of other viruses and the well-known suppressors HC-Pro and p19 but not of the potato mop-top virus p8 CRP. These results indicate that BNYVV- and TRV-encoded CRPs suppress RNA silencing more efficiently in roots than in leaves.
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Affiliation(s)
- Ida Bagus Andika
- Institute of Plant Science and Resources (IPSR), Okayama University, Kurashiki 710-0046, Japan
| | - Hideki Kondo
- Institute of Plant Science and Resources (IPSR), Okayama University, Kurashiki 710-0046, Japan
| | | | - Tetsuo Tamada
- Institute of Plant Science and Resources (IPSR), Okayama University, Kurashiki 710-0046, Japan
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Jelly NS, Schellenbaum P, Walter B, Maillot P. Transient expression of artificial microRNAs targeting Grapevine fanleaf virus and evidence for RNA silencing in grapevine somatic embryos. Transgenic Res 2012; 21:1319-27. [DOI: 10.1007/s11248-012-9611-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 03/07/2012] [Indexed: 01/18/2023]
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Abstract
Most of the 25 viruses found in globe artichoke (Cynara scolymus L.) and cardoon (Cynara cardunculus L.) were recorded from Europe and the Mediterranean basin, where they decrease both the productivity and the quality of the crop. Although, sometimes, these viruses are agents of diseases of different severity, most often their infections are symptomless. These conditions have contributed to spread virus-infected material since farmers multiply traditional artichoke types vegetatively with no effective selection of virus-free plants. This review reports the main properties of these viruses and the techniques used for their detection and identification. ELISA kits are commercially available for most of the viruses addressed in this review but have seldom been used for their detection in artichoke. Conversely, nucleic acid-based diagnostic reagents, some of which are commercially available, have successfully been employed to identify some viruses in artichoke sap. Control measures mainly use virus-free stocks for new plantations. A combined procedure of meristem-tip culture and thermotherapy proved useful for producing virus-free regenerants of the reflowering southern Italian cultivar Brindisino, which kept earliness and typical heads shape.
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Molecular characterization of Drosophila cells persistently infected with Flock House virus. Virology 2011; 419:43-53. [PMID: 21872290 DOI: 10.1016/j.virol.2011.08.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 06/06/2011] [Accepted: 08/04/2011] [Indexed: 11/24/2022]
Abstract
Little is known about the molecular determinants causing and sustaining viral persistent infections at the cellular level. We found that Drosophila cells persistently infected (PI) with Flock House virus (FHV) invariably harbor defective viral RNAs, which are replicated by the FHV RNA-dependent RNA polymerase. Some defective RNAs encoded a functional B2 protein, the FHV suppressor of RNA interference, which might contribute to maintenance of virus persistence. Viral small interfering RNAs (vsiRNAs) of both polarities were detected in PI cells and primarily mapped to regions of the viral genome that were preserved in the isolated defective RNAs. This indicated that defective RNAs could represent major sources of vsiRNAs. Immunofluorescence analysis revealed that mitochondria and viral proteins are differentially distributed in PI cells and lytically infected cells, which may partly explain the reduction in infectious viral progeny. Our results provide a basis for further investigations of the molecular mechanisms underlying persistent infections.
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Qian Y, Cheng Y, Cheng X, Jiang H, Zhu S, Cheng B. Identification and characterization of Dicer-like, Argonaute and RNA-dependent RNA polymerase gene families in maize. PLANT CELL REPORTS 2011; 30:1347-63. [PMID: 21404010 DOI: 10.1007/s00299-011-1046-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 02/13/2011] [Accepted: 02/26/2011] [Indexed: 05/20/2023]
Abstract
Eukaryotic gene expression is regulated at least by two processes, RNA interference at the post-transcriptional level and chromatin modification at the transcriptional level. Distinct small RNAs (approximately 21-24 nucleotides; sRNAs) were demonstrated to play vital roles in facilitating gene silencing. In plants, the generation of these sRNAs mainly depends on some proteins encoded by respective Dicer-like (DCL), Argonaute (AGO) and RNA-dependent RNA polymerases (RDR) gene families. Here, we analyzed the DCL, AGO and RDR gene families in maize, including gene structure, phylogenetic relationships, protein conserved motifs and genomic localization among gene family members. A total of 5 Zmdcl, 18 Zmago and 5 Zmrdr genes were identified in maize. Phylogenetic analyses clustered each of these genes families into four subfamilies. In addition, gene chromosomal localization revealed that five pairs of Zmago genes resulted from tandem or segmental duplication, respectively. EST expression data mining revealed that these newly identified genes had temporal and spatial expression pattern. Furthermore, the transcripts of these genes were detected in the leaves by two different abiotic stress treatments using semi-quantitative RT-PCR. The data demonstrated that these genes exhibited different expression levels in stress treatments. The results of this study provided basic genomic information for these gene families and insights into the probable roles of these genes in plant growth and development. This will further provide a solid foundation for future functional genomics studies of Dicer-like, Argonaute and RDR gene families in maize.
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Affiliation(s)
- Yexiong Qian
- Key Laboratory of Crop Biology, Anhui Agricultural University, Hefei, China.
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Jovel J, Walker M, Sanfaçon H. Salicylic acid-dependent restriction of Tomato ringspot virus spread in tobacco is accompanied by a hypersensitive response, local RNA silencing, and moderate systemic resistance. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:706-18. [PMID: 21281112 DOI: 10.1094/mpmi-09-10-0224] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Tomato ringspot virus (ToRSV, a Nepovirus sp.) systemically infects many herbaceous plants. Viral RNA accumulates in symptomatic leaves and in young, asymptomatic leaves that emerge late in infection. Here, we show that systemic infection by ToRSV is restricted in tobacco. After an initial hypersensitive response in inoculated leaves, only a few plants showed limited systemic symptoms. Viral RNA did not usually accumulate to detectable levels in asymptomatic leaves. ToRSV-derived small-interfering RNAs and PR1a transcripts were only detected in tissues that contained viral RNA, indicating local induction of RNA silencing and salicylic acid (SA)-dependent defense responses. Lesion size and viral systemic spread were reduced with SA pretreatment but enhanced in NahG transgenic lines deficient in SA accumulation, suggesting that SA-dependent mechanisms play a key role in limiting ToRSV spread in tobacco. Restriction of virus infection was enhanced in transgenic lines expressing the P1-HC-Pro suppressor of silencing. Knocking down the SA-inducible RNA-dependent RNA polymerase 1 exacerbated the necrotic reaction but did not affect viral systemic spread. ToRSV-infected tobacco plants were susceptible to reinoculation by ToRSV or Tobacco mosaic virus, although a small reduction in lesion size was observed. This moderate systemic resistance suggests inefficient induction or spread of RNA silencing and systemic acquired resistance signal molecules.
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Affiliation(s)
- Juan Jovel
- Pacific Agri-Food Research Centre, Agriculture and Agri-Food, Canada
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Lim HS, Vaira AM, Reinsel MD, Bae H, Bailey BA, Domier LL, Hammond J. Pathogenicity of Alternanthera mosaic virus is affected by determinants in RNA-dependent RNA polymerase and by reduced efficacy of silencing suppression in a movement-competent TGB1. J Gen Virol 2010; 91:277-87. [PMID: 20019006 DOI: 10.1099/vir.0.014977-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Four biologically active cDNA clones were derived from the Alternanthera mosaic virus (AltMV; genus Potexvirus) isolate, AltMV-SP, which differ in symptoms in infected Nicotiana benthamiana plants. Two clones induced necrosis and plant death; a mixture of all four clones induced milder symptoms than AltMV-SP. Replication of all clones was enhanced by a minimum of fourfold at 15 degrees C. A mixture of clones 4-7 (severe) and 3-1 (mild) was indistinguishable from AltMV-SP, but the ratio of 4-7 to 3-1 differed at 25 and 15 degrees C. RNA copy numbers of mixed infections were always below those of 4-7 alone. Determinants of symptom severity were identified in both Pol and TGB1; the mildest (4-1) and most severe (3-7) clones differed at three residues in the 'core' Pol domain [R(1110)P, K(1121)R, R(1255)K] and one [S(1535)P] in the C-terminal Pol domain of RNA-dependent RNA polymerase, and one in TGB1 [P(88)L]. Pol [P(1110),R(1121),K(1255)]+TGB1(L(88))] always induced systemic necrosis at 15 degrees C. Gene exchanges of Pol and TGB1 each affected replication and symptom expression, with TGB1(P(88)) significantly reducing silencing suppression. The difference in silencing suppression between TGB1(P(88)) and TGB1(L(88)) was confirmed by an agroinfiltration assay. Further, co-expression of TGB1(P(88)) and TGB1(L(88)) resulted in interference in the suppression of silencing by TGB1(L(88)). Yeast two-hybrid analysis confirmed that TGB1(P(88)) and TGB1(L(88)) interact. These results identify a TGB1 residue that significantly affects replication and silencing suppression, but maintains full movement functions.
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Affiliation(s)
- Hyoun-Sub Lim
- USDA-ARS, USNA, Floral and Nursery Plants Research Unit, Beltsville, MD 20705, USA
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Insertion of large amino acid repeats and point mutations contribute to a high degree of sequence diversity in the X4 protein of tomato ringspot virus (genus Nepovirus). Arch Virol 2009; 154:1713-7. [DOI: 10.1007/s00705-009-0497-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 08/14/2009] [Indexed: 10/20/2022]
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Isolation, expression and functional analysis of a putative RNA-dependent RNA polymerase gene from maize (Zea mays L.). Mol Biol Rep 2009; 37:865-74. [PMID: 19685166 DOI: 10.1007/s11033-009-9692-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2009] [Accepted: 07/28/2009] [Indexed: 10/20/2022]
Abstract
RNA-dependent RNA polymerases (RdRPs) in plants have been reported to be involved in post-transcriptional gene silencing (PTGS) and antiviral defense. In this report, an RdRP gene from maize (ZmRdRP1) was obtained by rapid amplification of cDNA ends (RACE) and RT-PCR. The mRNA of ZmRdRP1 was composed of 3785 nucleotides, including a 167 nt 5' untranslated region (UTR), a 291 nt 3'UTR and a 3327 nt open reading frame (ORF), which encodes a putative protein of 1108 amino acids with an estimated molecular mass of 126.9 kDa and a predicated isoelectric point (pI) of 8.37. Real-time quantitative RT-PCR analysis showed that ZmRdRP1 was elicited by salicylic acid (SA) treatment, methyl jasmonate (MeJA) treatment and sugarcane mosaic virus (SCMV) infection. We silenced ZmRdRP1 by constitutively expressing an inverted-repeat fragment of ZmRdRP1 (ir-RdRP1) in transgenic maize plants. Further studies revealed that the ir-RdRP1 transgenic plants were more susceptible to SCMV infection than wild type plants. Virus-infected transgenic maize plants developed more serious disease symptoms and accumulated more virus than wild type plants. These findings suggested that ZmRdRP1 was involved in antiviral defense in maize.
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Lewsey M, Surette M, Robertson FC, Ziebell H, Choi SH, Ryu KH, Canto T, Palukaitis P, Payne T, Walsh JA, Carr JP. The role of the Cucumber mosaic virus 2b protein in viral movement and symptom induction. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:642-54. [PMID: 19445589 DOI: 10.1094/mpmi-22-6-0642] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The Cucumber mosaic virus (CMV) 2b protein is a counter-defense factor and symptom determinant. Conserved domains in the 2b protein sequence were mutated in the 2b gene of strain Fny-CMV. The effects of these mutations were assessed by infection of Nicotiana tabacum, N. benthamiana, and Arabidopsis thaliana (ecotype Col-0) with mutant viruses and by expression of mutant 2b transgenes in A. thaliana. We confirmed that two nuclear localization signals were required for symptom induction and found that the N-terminal domain was essential for symptom induction. The C-terminal domain and two serine residues within a putative phosphorylation domain modulated symptom severity. Further infection studies were conducted using Fny-CMVdelta2b, a mutant that cannot express the 2b protein and that induces no symptoms in N. tabacum, N. benthamiana, or A. thaliana ecotype Col-0. Surprisingly, in plants of A. thaliana ecotype C24, Fny-CMVdelta2b induced severe symptoms similar to those induced by the wild-type virus. However, C24 plants infected with the mutant virus recovered from disease while those infected with the wild-type virus did not. Expression of 2b transgenes from either Fny-CMV or from LS-CMV (a mild strain) in Col-0 plants enhanced systemic movement of Fny-CMVdelta2b and permitted symptom induction by Fny-CMVdelta2b. Taken together, the results indicate that the 2b protein itself is an important symptom determinant in certain hosts. However, they also suggest that the protein may somehow synergize symptom induction by other CMV-encoded factors.
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Affiliation(s)
- Mathew Lewsey
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
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Groenenboom MAC, Hogeweg P. RNA silencing can explain chlorotic infection patterns on plant leaves. BMC SYSTEMS BIOLOGY 2008; 2:105. [PMID: 19040760 PMCID: PMC2633331 DOI: 10.1186/1752-0509-2-105] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 11/30/2008] [Indexed: 12/31/2022]
Abstract
Background RNA silencing has been implicated in virus symptom development in plants. One common infection symptom in plants is the formation of chlorotic tissue in leaves. Chlorotic and healthy tissue co-occur on a single leaf and form patterns. It has been shown that virus levels in chlorotic tissue are high, while they are low in healthy tissue. Additionally, the presence of siRNAs is confined to the chlorotic spots and the boundaries between healthy and infected tissue. These results strongly indicate that the interaction between virus growth and RNA silencing plays a role in the formation of infection patterns on leaves. However, how RNA silencing leads to the intricate patterns is not known. Results Here we elucidate the mechanisms leading to infection patterns and the conditions which lead to the various patterns observed. We present a modeling approach in which we combine intra- and inter-cellular dynamics of RNA silencing and viral growth. We observe that, due to the spread of viruses and the RNA silencing response, parts of the tissue become infected while other parts remain healthy. As is observed in experiments high virus levels coincide with high levels of siRNAs, and siRNAs are also present in the boundaries between infected and healthy tissue. We study how single- and double-stranded cleavage by Dicer and amplification by RNA-dependent RNA polymerase can affect the patterns formed. Conclusion This work shows that RNA silencing and virus growth within a cell, and the local spread of virions and siRNAs between cells can explain the heterogeneous spread of virus in leaf tissue, and therewith the observed infection patterns in plants.
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Affiliation(s)
- Marian A C Groenenboom
- Theoretical Biology and Bioinformatics, University of Utrecht, Padualaan 8, 3584 CH Utrecht, the Netherlands.
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