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Choi J, Browning S, Schmitt-Keichinger C, Fuchs M. Mutations in the WG and GW motifs of the three RNA silencing suppressors of grapevine fanleaf virus alter their systemic suppression ability and affect virus infectivity. Front Microbiol 2024; 15:1451285. [PMID: 39188317 PMCID: PMC11345138 DOI: 10.3389/fmicb.2024.1451285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Accepted: 07/31/2024] [Indexed: 08/28/2024] Open
Abstract
Viral suppressors of RNA silencing (VSRs) encoded by grapevine fanleaf virus (GFLV), one of the most economically consequential viruses of grapevine (Vitis spp.), were recently identified. GFLV VSRs include the RNA1-encoded protein 1A and the putative helicase protein 1BHel, as well as their fused form (1ABHel). Key characteristics underlying the suppression function of the GFLV VSRs are unknown. In this study, we explored the role of the conserved tryptophan-glycine (WG) motif in protein 1A and glycine-tryptophan (GW) motif in protein 1BHel in their systemic RNA silencing suppression ability by co-infiltrating Nicotiana benthamiana 16c line plants with a GFP silencing construct and a wildtype or a mutant GFLV VSR. We analyzed and compared wildtype and mutant GFLV VSRs for their (i) efficiency at suppressing RNA silencing, (ii) ability to limit siRNA accumulation, (iii) modulation of the expression of six host genes involved in RNA silencing, (iv) impact on virus infectivity in planta, and (v) variations in predicted protein structures using molecular and biochemical assays, as well as bioinformatics tools such as AlphaFold2. Mutating W to alanine (A) in WG of proteins 1A and 1ABHel abolished their ability to induce systemic RNA silencing suppression, limit siRNA accumulation, and downregulate NbAGO2 expression by 1ABHel. This mutation in the GFLV genome resulted in a non-infectious virus. Mutating W to A in GW of proteins 1BHel and 1ABHel reduced their ability to suppress systemic RNA silencing and abolished the downregulation of NbDCL2, NbDCL4,, and NbRDR6 expression by 1BHel. This mutation in the GFLV genome delayed infection at the local level and inhibited systemic infection in planta. Double mutations of W to A in WG and GW of protein 1ABHel abolished its ability to induce RNA silencing suppression, limit siRNA accumulation, and downregulate NbDCL2 and NbRDR6 expression. Finally, in silico protein structure prediction indicated that a W to A substitution potentially modifies the structure and physicochemical properties of the three GFLV VSRs. Together, this study provided insights into the specific roles of WG/GW not only in GFLV VSR functions but also in GFLV biology.
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Affiliation(s)
- Jiyeong Choi
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science College of Agriculture and Life Sciences, Cornell University, Cornell AgriTech at the New York State Agricultural Experiment Station, Geneva, NY, United States
| | - Scottie Browning
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science College of Agriculture and Life Sciences, Cornell University, Cornell AgriTech at the New York State Agricultural Experiment Station, Geneva, NY, United States
| | - Corinne Schmitt-Keichinger
- CNRS, IBMP UPR 2357, Université de Strasbourg, Strasbourg, France
- INRAE, SVQV UMR 1131, Université de Strasbourg, Colmar, France
| | - Marc Fuchs
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science College of Agriculture and Life Sciences, Cornell University, Cornell AgriTech at the New York State Agricultural Experiment Station, Geneva, NY, United States
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Crawshaw S, Murphy AM, Rowling PJE, Nietlispach D, Itzhaki LS, Carr JP. Investigating the Interactions of the Cucumber Mosaic Virus 2b Protein with the Viral 1a Replicase Component and the Cellular RNA Silencing Factor Argonaute 1. Viruses 2024; 16:676. [PMID: 38793558 PMCID: PMC11125589 DOI: 10.3390/v16050676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 04/13/2024] [Accepted: 04/16/2024] [Indexed: 05/26/2024] Open
Abstract
The cucumber mosaic virus (CMV) 2b protein is a suppressor of plant defenses and a pathogenicity determinant. Amongst the 2b protein's host targets is the RNA silencing factor Argonaute 1 (AGO1), which it binds to and inhibits. In Arabidopsis thaliana, if 2b-induced inhibition of AGO1 is too efficient, it induces reinforcement of antiviral silencing by AGO2 and triggers increased resistance against aphids, CMV's insect vectors. These effects would be deleterious to CMV replication and transmission, respectively, but are moderated by the CMV 1a protein, which sequesters sufficient 2b protein molecules into P-bodies to prevent excessive inhibition of AGO1. Mutant 2b protein variants were generated, and red and green fluorescent protein fusions were used to investigate subcellular colocalization with AGO1 and the 1a protein. The effects of mutations on complex formation with the 1a protein and AGO1 were investigated using bimolecular fluorescence complementation and co-immunoprecipitation assays. Although we found that residues 56-60 influenced the 2b protein's interactions with the 1a protein and AGO1, it appears unlikely that any single residue or sequence domain is solely responsible. In silico predictions of intrinsic disorder within the 2b protein secondary structure were supported by circular dichroism (CD) but not by nuclear magnetic resonance (NMR) spectroscopy. Intrinsic disorder provides a plausible model to explain the 2b protein's ability to interact with AGO1, the 1a protein, and other factors. However, the reasons for the conflicting conclusions provided by CD and NMR must first be resolved.
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Affiliation(s)
- Sam Crawshaw
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (S.C.); (A.M.M.)
| | - Alex M. Murphy
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (S.C.); (A.M.M.)
| | - Pamela J. E. Rowling
- Department of Pharmacology, University of Cambridge, Tennis Court Rd., Cambridge CB2 1PD, UK; (P.J.E.R.); (L.S.I.)
| | - Daniel Nietlispach
- Department of Biochemistry, University of Cambridge, Sanger Building, 80 Tennis Court Rd., Cambridge CB2 1GA, UK;
| | - Laura S. Itzhaki
- Department of Pharmacology, University of Cambridge, Tennis Court Rd., Cambridge CB2 1PD, UK; (P.J.E.R.); (L.S.I.)
| | - John P. Carr
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (S.C.); (A.M.M.)
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Zhang T, Li C, Zhu J, Li Y, Wang Z, Tong CY, Xi Y, Han Y, Koiwa H, Peng X, Zhang X. Structured 3' UTRs destabilize mRNAs in plants. Genome Biol 2024; 25:54. [PMID: 38388963 PMCID: PMC10885604 DOI: 10.1186/s13059-024-03186-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 02/14/2024] [Indexed: 02/24/2024] Open
Abstract
BACKGROUND RNA secondary structure (RSS) can influence the regulation of transcription, RNA processing, and protein synthesis, among other processes. 3' untranslated regions (3' UTRs) of mRNA also hold the key for many aspects of gene regulation. However, there are often contradictory results regarding the roles of RSS in 3' UTRs in gene expression in different organisms and/or contexts. RESULTS Here, we incidentally observe that the primary substrate of miR159a (pri-miR159a), when embedded in a 3' UTR, could promote mRNA accumulation. The enhanced expression is attributed to the earlier polyadenylation of the transcript within the hybrid pri-miR159a-3' UTR and, resultantly, a poorly structured 3' UTR. RNA decay assays indicate that poorly structured 3' UTRs could promote mRNA stability, whereas highly structured 3' UTRs destabilize mRNA in vivo. Genome-wide DMS-MaPseq also reveals the prevailing inverse relationship between 3' UTRs' RSS and transcript accumulation in the transcriptomes of Arabidopsis, rice, and even human. Mechanistically, transcripts with highly structured 3' UTRs are preferentially degraded by 3'-5' exoribonuclease SOV and 5'-3' exoribonuclease XRN4, leading to decreased expression in Arabidopsis. Finally, we engineer different structured 3' UTRs to an endogenous FT gene and alter the FT-regulated flowering time in Arabidopsis. CONCLUSIONS We conclude that highly structured 3' UTRs typically cause reduced accumulation of the harbored transcripts in Arabidopsis. This pattern extends to rice and even mammals. Furthermore, our study provides a new strategy of engineering the 3' UTRs' RSS to modify plant traits in agricultural production and mRNA stability in biotechnology.
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Affiliation(s)
- Tianru Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
- Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Changhao Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Jiaying Zhu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA.
| | - Yanjun Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Zhiye Wang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Chun-Yip Tong
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Yu Xi
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, 77807, USA
| | - Yi Han
- National Engineering Laboratory of Crop Stress Resistence Breeding, School of Life Sciences, Anhui Agricultural University, Hefei, 230036, China
| | - Hisashi Koiwa
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Xu Peng
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, 77807, USA
| | - Xiuren Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA.
- Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX, 77843, USA.
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA.
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Xu X, Lou Y, Liang K, Liu J, Wang Z, Chen B, Li W. The P2 nucleic acid binding protein of Sugarcane bacilliform virus is a viral pathogenic factor. PeerJ 2024; 12:e16982. [PMID: 38406282 PMCID: PMC10885806 DOI: 10.7717/peerj.16982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 01/30/2024] [Indexed: 02/27/2024] Open
Abstract
Background Saccharum spp. is the primary source of sugar and plays a significant role in global renewable bioenergy. Sugarcane bacilliform virus (SCBV) is one of the most important viruses infecting sugarcane, causing severe yield losses and quality degradation. It is of great significance to reveal the pathogenesis of SCBV and resistance breeding. However, little is known about the viral virulence factors or RNA silencing suppressors and the molecular mechanism of pathogenesis. Methods To systematically investigate the functions of the unknown protein P2 encoded by SCBV ORF2. Phylogenetic analysis was implemented to infer the evolutionary relationship between the P2 of SCBV and other badnaviruses. The precise subcellular localization of P2 was verified in the transient infiltrated Nicotiana benthamiana epidermal mesophyll cells and protoplasts using the Laser scanning confocal microscope (LSCM). The post-transcriptional gene silencing (PTGS) and transcriptional gene silencing (TGS) RNA silencing suppressor activity of P2 was analyzed, respectively. Furthermore, restriction digestion and RT-qPCR assays were conducted to verify the probable mechanism of P2 on repressing DNA methylation. To explore the pathogenicity of P2, a potato virus X-based viral vector was used to heterologously express SCBV P2 and the consequent H2O2 accumulation was detected by the 3,3'-diaminobenzidine (DAB) staining method. Results Phylogenetic analysis shows that SCBV has no obvious sequence similarity and low genetic relatedness to Badnavirus and Tungrovirus representatives. LSCM studies show that P2 is localized in both the cytoplasm and nucleus. Moreover, P2 is shown to be a suppressor of PTGS and TGS, which can not only repress ssRNA-induced gene silencing but also disrupt the host RNA-directed DNA methylation (RdDM) pathway. In addition, P2 can trigger an oxidative burst and cause typical hypersensitive-like response (HLR) necrosis in systemic leaves of N. benthamiana when expressed by PVX. Overall, our results laid a foundation for deciphering the molecular mechanism of SCBV pathogenesis and made progress for resistance breeding.
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Affiliation(s)
- Xiongbiao Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Yinian Lou
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Kaili Liang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Jingying Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Zhiyuan Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Baoshan Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Wenlan Li
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
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Leastro MO, Pallás V, Sánchez-Navarro JÁ. The capsid protein of citrus leprosis virus C shows a nuclear distribution and interacts with the nucleolar fibrillarin protein. Virus Res 2024; 340:199297. [PMID: 38070688 PMCID: PMC10758971 DOI: 10.1016/j.virusres.2023.199297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/29/2023] [Accepted: 12/06/2023] [Indexed: 01/05/2024]
Abstract
Brevipalpus-transmitted viruses (BTVs) have a significant negative economic impact on the citrus industry in Central and South America. Until now, only a few studies have explored the intracellular distribution and interaction of BTVs-encoded proteins with host factors, particularly for cileviruses, the main BTV responsible for the Citrus Leprosis (CL) disease. This study describes the nuclear localization of citrus leprosis virus C (CiLV-C) capsid protein (p29) and its interaction with the fibrillarin (Fib2) within the nucleolar compartment and cell cytoplasm. Our results, obtained by computer predictions and laser scanning confocal microscopy analyses, including colocalization and bimolecular fluorescence complementation (BiFC) approaches, revealed that a fraction of the p29 is localized in the nucleus and colocalizes with the Fib2 in both the nucleolus and cytosol. The nuclear localization of p29 correlated with a smaller nucleus size. Furthermore, co-immunoprecipitation (Co-IP) assays confirmed the interactions between p29 and Fib2. The implications of these findings for the functionalities of the cilevirus capsid protein are discussed.
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Affiliation(s)
- Mikhail Oliveira Leastro
- Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de Valencia-Consejo Superior de Investigaciones Científicas (CSIC), Valencia 46022, Spain.
| | - Vicente Pallás
- Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de Valencia-Consejo Superior de Investigaciones Científicas (CSIC), Valencia 46022, Spain
| | - Jesús Ángel Sánchez-Navarro
- Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de Valencia-Consejo Superior de Investigaciones Científicas (CSIC), Valencia 46022, Spain.
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6
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Kirov I. Toward Transgene-Free Transposon-Mediated Biological Mutagenesis for Plant Breeding. Int J Mol Sci 2023; 24:17054. [PMID: 38069377 PMCID: PMC10706983 DOI: 10.3390/ijms242317054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Genetic diversity is a key factor for plant breeding. The birth of novel genic and genomic variants is also crucial for plant adaptation in nature. Therefore, the genomes of almost all living organisms possess natural mutagenic mechanisms. Transposable elements (TEs) are a major mutagenic force driving genetic diversity in wild plants and modern crops. The relatively rare TE transposition activity during the thousand-year crop domestication process has led to the phenotypic diversity of many cultivated species. The utilization of TE mutagenesis by artificial and transient acceleration of their activity in a controlled mode is an attractive foundation for a novel type of mutagenesis called TE-mediated biological mutagenesis. Here, I focus on TEs as mutagenic sources for plant breeding and discuss existing and emerging transgene-free approaches for TE activation in plants. Furthermore, I also review the non-randomness of TE insertions in a plant genome and the molecular and epigenetic factors involved in shaping TE insertion preferences. Additionally, I discuss the molecular mechanisms that prevent TE transpositions in germline plant cells (e.g., meiocytes, pollen, egg and embryo cells, and shoot apical meristem), thereby reducing the chances of TE insertion inheritance. Knowledge of these mechanisms can expand the TE activation toolbox using novel gene targeting approaches. Finally, the challenges and future perspectives of plant populations with induced novel TE insertions (iTE plant collections) are discussed.
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Affiliation(s)
- Ilya Kirov
- All-Russia Research Institute of Agricultural Biotechnology, 127550 Moscow, Russia;
- Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
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Li M, Zhang X, Huang K, Du Z. Identification of Host Factors Interacting with a γ-Shaped RNA Element from a Plant Virus-Associated Satellite RNA. Viruses 2023; 15:2039. [PMID: 37896816 PMCID: PMC10611174 DOI: 10.3390/v15102039] [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: 09/15/2023] [Revised: 09/28/2023] [Accepted: 09/29/2023] [Indexed: 10/29/2023] Open
Abstract
Previously, we identified a highly conserved, γ-shaped RNA element (γRE) from satellite RNAs of cucumber mosaic virus (CMV), and we determined γRE to be structurally required for satRNA survival and the inhibition of CMV replication. It remains unknown how γRE biologically functions. In this work, pull-down assays were used to screen candidates of host factors from Nicotiana benthamiana plants using biotin-labeled γRE as bait. Nine host factors were found to interact specifically with γRE. Then, all of these host factors were down-regulated individually in N. benthamiana plants via tobacco rattle virus-induced gene silencing and tested with infection by GFP-expressing CMV (CMV-gfp) and the isolate T1 of satRNA (sat-T1). Out of nine candidates, three host factors, namely histone H3, GTPase Ran3, and eukaryotic translation initiation factor 4A, were extremely important for infection by CMV-gfp and sat-T1. Moreover, we found that cytosolic glyceraldehyde-3-phosphate dehydrogenase 2 contributed to the replication of CMV and sat-T1, but also negatively regulated CMV 2b activity. Collectively, our work provides essential clues for uncovering the mechanism by which satRNAs inhibit CMV replication.
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Affiliation(s)
| | | | | | - Zhiyou Du
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
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8
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Tong X, Zhao JJ, Feng YL, Zou JZ, Ye J, Liu J, Han C, Li D, Wang XB. A selective autophagy receptor VISP1 induces symptom recovery by targeting viral silencing suppressors. Nat Commun 2023; 14:3852. [PMID: 37385991 PMCID: PMC10310818 DOI: 10.1038/s41467-023-39426-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 06/09/2023] [Indexed: 07/01/2023] Open
Abstract
Selective autophagy is a double-edged sword in antiviral immunity and regulated by various autophagy receptors. However, it remains unclear how to balance the opposite roles by one autophagy receptor. We previously identified a virus-induced small peptide called VISP1 as a selective autophagy receptor that facilitates virus infections by targeting components of antiviral RNA silencing. However, we show here that VISP1 can also inhibit virus infections by mediating autophagic degradation of viral suppressors of RNA silencing (VSRs). VISP1 targets the cucumber mosaic virus (CMV) 2b protein for degradation and attenuates its suppression activity on RNA silencing. Knockout and overexpression of VISP1 exhibit compromised and enhanced resistance against late infection of CMV, respectively. Consequently, VISP1 induces symptom recovery from CMV infection by triggering 2b turnover. VISP1 also targets the C2/AC2 VSRs of two geminiviruses and enhances antiviral immunity. Together, VISP1 induces symptom recovery from severe infections of plant viruses through controlling VSR accumulation.
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Affiliation(s)
- Xin Tong
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
- College of Plant Protection, China Agricultural University, 100193, Beijing, China
| | - Jia-Jia Zhao
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Ya-Lan Feng
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Jing-Ze Zou
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Jian Ye
- State Key laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Junfeng Liu
- College of Plant Protection, China Agricultural University, 100193, Beijing, China
| | - Chenggui Han
- College of Plant Protection, China Agricultural University, 100193, Beijing, China
| | - Dawei Li
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Xian-Bing Wang
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China.
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Liu S, Han Y, Li WX, Ding SW. Infection Defects of RNA and DNA Viruses Induced by Antiviral RNA Interference. Microbiol Mol Biol Rev 2023; 87:e0003522. [PMID: 37052496 PMCID: PMC10304667 DOI: 10.1128/mmbr.00035-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023] Open
Abstract
Immune recognition of viral genome-derived double-stranded RNA (dsRNA) molecules and their subsequent processing into small interfering RNAs (siRNAs) in plants, invertebrates, and mammals trigger specific antiviral immunity known as antiviral RNA interference (RNAi). Immune sensing of viral dsRNA is sequence-independent, and most regions of viral RNAs are targeted by virus-derived siRNAs which extensively overlap in sequence. Thus, the high mutation rates of viruses do not drive immune escape from antiviral RNAi, in contrast to other mechanisms involving specific virus recognition by host immune proteins such as antibodies and resistance (R) proteins in mammals and plants, respectively. Instead, viruses actively suppress antiviral RNAi at various key steps with a group of proteins known as viral suppressors of RNAi (VSRs). Some VSRs are so effective in virus counter-defense that potent inhibition of virus infection by antiviral RNAi is undetectable unless the cognate VSR is rendered nonexpressing or nonfunctional. Since viral proteins are often multifunctional, resistance phenotypes of antiviral RNAi are accurately defined by those infection defects of VSR-deletion mutant viruses that are efficiently rescued by host deficiency in antiviral RNAi. Here, we review and discuss in vivo infection defects of VSR-deficient RNA and DNA viruses resulting from the actions of host antiviral RNAi in model systems.
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Affiliation(s)
- Si Liu
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, USA
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
| | - Yanhong Han
- Vector-borne Virus Research Center, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Wan-Xiang Li
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, USA
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
| | - Shou-Wei Ding
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, USA
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
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10
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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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11
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Zhao L, Chen Y, Xiao X, Gao H, Cao J, Zhang Z, Guo Z. AGO2a but not AGO2b mediates antiviral defense against infection of wild-type cucumber mosaic virus in tomato. HORTICULTURE RESEARCH 2023; 10:uhad043. [PMID: 37188058 PMCID: PMC10177002 DOI: 10.1093/hr/uhad043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 03/05/2023] [Indexed: 05/17/2023]
Abstract
Evolutionarily conserved antiviral RNA interference (RNAi) mediates a primary antiviral innate immunity preventing infection of broad-spectrum viruses in plants. However, the detailed mechanism in plants is still largely unknown, especially in important agricultural crops, including tomato. Varieties of pathogenic viruses evolve to possess viral suppressors of RNA silencing (VSRs) to suppress antiviral RNAi in the host. Due to the prevalence of VSRs, it is still unknown whether antiviral RNAi truly functions to prevent invasion by natural wild-type viruses in plants and animals. In this research, for the first time we applied CRISPR-Cas9 to generate ago2a, ago2b, or ago2ab mutants for two differentiated Solanum lycopersicum AGO2s, key effectors in antiviral RNAi. We found that AGO2a but not AGO2b was significantly induced to inhibit the propagation of not only VSR-deficient Cucumber mosaic virus (CMV) but also wild-type CMV-Fny in tomato; however, neither AGO2a nor AGO2b regulated disease induction after infection with either virus. Our findings firstly reveal a prominent role of AGO2a in antiviral RNAi innate immunity in tomato and demonstrate that antiviral RNAi evolves to defend against infection of natural wild-type CMV-Fny in tomato. However, AGO2a-mediated antiviral RNAi does not play major roles in promoting tolerance of tomato plants to CMV infection for maintaining health.
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Affiliation(s)
| | | | - Xingming Xiao
- Vector-borne Virus Research Center, State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002 China
| | - Haiying Gao
- Vector-borne Virus Research Center, State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002 China
| | - Jiamin Cao
- Vector-borne Virus Research Center, State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002 China
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12
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Ding SW. Transgene Silencing, RNA Interference, and the Antiviral Defense Mechanism Directed by Small Interfering RNAs. PHYTOPATHOLOGY 2023; 113:616-625. [PMID: 36441873 DOI: 10.1094/phyto-10-22-0358-ia] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
One important discovery in plant pathology over recent decades is the natural antiviral defense mechanism mediated by RNA interference (RNAi). In antiviral RNAi, virus infection triggers Dicer processing of virus-specific double-stranded RNA into small interfering RNAs (siRNAs). Frequently, further amplified by host enzyme and cofactors, these virus-derived siRNAs direct specific virus clearance in an Argonaute protein-containing effector complex. The siRNAs derived from viruses and viroids accumulate to very high levels during infection. Because they overlap extensively in nucleotide sequence, this allows for deep sequencing and bioinformatics assembly of total small RNAs for rapid discovery and identification of viruses and viroids. Antiviral RNAi acts as the primary defense mechanism against both RNA and DNA viruses in plants, yet viruses still successfully infect plants. They do so because all currently recognized plant viruses combat the RNAi response by encoding at least one protein as a viral suppressor of RNAi (VSR) required for infection, even though plant viruses have small genome sizes with a limited coding capacity. This review article will recapitulate the key findings that have revealed the genetic pathway for the biogenesis and antiviral activity of viral siRNAs and the specific role of VSRs in infection by antiviral RNAi suppression. Moreover, early pioneering studies on transgene silencing, RNAi, and virus-plant/virus-virus interactions paved the road to the discovery of antiviral RNAi.
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Affiliation(s)
- Shou-Wei Ding
- Department of Microbiology & Plant Pathology and Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA
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13
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Silencing suppressor protein PRT of rice tungro bacilliform virus interacts with the plant RNA silencing-related protein SGS3. Virology 2023; 581:71-80. [PMID: 36921478 DOI: 10.1016/j.virol.2023.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 02/16/2023] [Accepted: 02/22/2023] [Indexed: 03/08/2023]
Abstract
BACKGROUND Rice tungro bacilliform virus (RTBV) is a double stranded DNA containing virus which causes the devastating tungro disease of rice in association with an RNA virus, rice tungro spherical virus. RNA silencing is an evolutionarily conserved antiviral defence pathway in plants as well as in several classes of higher organisms. Many viruses, in turn, encode proteins which are termed Viral Suppressor of RNA Silencing (VSR) because they downregulate or suppress RNA silencing. RESULTS Using an RNA silencing suppressor assay we show that RTBV protease (PRT) acts as a mild VSR. A truncated version of PRT gene abolished the silencing suppression activity. We also show in planta interaction of PRT with the SGS3 protein of Solanum tuberosum and Arabidopsis thaliana using bimolecular fluorescence complementation assay (BIFC). Transient expression of PRT in Nicotiana benthamiana caused an increased accumulation of the begomovirus Sri Lankan cassava mosaic virus (SLCMV) DNA-A, which indicated a virulence function imparted on an unrelated virus. CONCLUSION The finding supports the idea that PRT acts as suppressor of RNA silencing and this action may be mediated by its interaction with SGS3.
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14
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Hong SF, Fang RY, Wei WL, Jirawitchalert S, Pan ZJ, Hung YL, Pham TH, Chiu YH, Shen TL, Huang CK, Lin SS. Development of an assay system for the analysis of host RISC activity in the presence of a potyvirus RNA silencing suppressor, HC-Pro. Virol J 2023; 20:10. [PMID: 36650505 PMCID: PMC9844029 DOI: 10.1186/s12985-022-01956-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/18/2022] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND To investigate the mechanism of RNA silencing suppression, the genetic transformation of viral suppressors of RNA silencing (VSRs) in Arabidopsis integrates ectopic VSR expression at steady state, which overcomes the VSR variations caused by different virus infections or limitations of host range. Moreover, identifying the insertion of the transgenic VSR gene is necessary to establish a model transgenic plant for the functional study of VSR. METHODS Developing an endogenous AGO1-based in vitro RNA-inducing silencing complex (RISC) assay prompts further investigation into VSR-mediated suppression. Three P1/HC-Pro plants from turnip mosaic virus (TuMV) (P1/HC-ProTu), zucchini yellow mosaic virus (ZYMV) (P1/HC-ProZy), and tobacco etch virus (TEV) (P1/HC-ProTe) were identified by T-DNA Finder and used as materials for investigations of the RISC cleavage efficiency. RESULTS Our results indicated that the P1/HC-ProTu plant has slightly lower RISC activity than P1/HC-ProZy plants. In addition, the phenomena are consistent with those observed in TuMV-infected Arabidopsis plants, which implies that HC-ProTu could directly interfere with RISC activity. CONCLUSIONS In this study, we demonstrated the application of various plant materials in an in vitro RISC assay of VSR-mediated RNA silencing suppression.
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Affiliation(s)
- Syuan-Fei Hong
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Ru-Ying Fang
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Wei-Lun Wei
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Supidcha Jirawitchalert
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Zhao-Jun Pan
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Yu-Ling Hung
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Thanh Ha Pham
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Yen-Hsin Chiu
- grid.19188.390000 0004 0546 0241Institute of Biotechnology, National Taiwan University, Taipei, 106 Taiwan ,grid.453140.70000 0001 1957 0060Seed Improvement and Propagation Station, Council of Agriculture, Taichung, 427 Taiwan
| | - Tang-Long Shen
- grid.19188.390000 0004 0546 0241Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, 106 Taiwan ,grid.19188.390000 0004 0546 0241Center of Biotechnology, National Taiwan University, Taipei, 106 Taiwan
| | - Chien-Kang Huang
- Department of Computer Science and Information Engineering, National Taiwan University, Taipei, 106, Taiwan.
| | - Shih-Shun Lin
- Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan. .,Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan. .,Center of Biotechnology, National Taiwan University, Taipei, 106, Taiwan.
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15
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Nishiguchi M, Ali ME, Kaya T, Kobayashi K. Plant virus disease control by vaccination and transgenic approaches: Current status and perspective. PLANT RNA VIRUSES 2023:373-424. [DOI: 10.1016/b978-0-323-95339-9.00028-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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16
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Abstract
Adaptive antiviral immunity in plants is an RNA-based mechanism in which small RNAs derived from both strands of the viral RNA are guides for an Argonaute (AGO) nuclease. The primed AGO specifically targets and silences the viral RNA. In plants this system has diversified to involve mobile small interfering RNAs (siRNAs), an amplification system involving secondary siRNAs and targeting mechanisms involving DNA methylation. Most, if not all, plant viruses encode multifunctional proteins that are suppressors of RNA silencing that may also influence the innate immune system and fine-tune the virus-host interaction. Animal viruses similarly trigger RNA silencing, although it may be masked in differentiated cells by the interferon system and by the action of the virus-encoded suppressor proteins. There is huge potential for RNA silencing to combat viral disease in crops, farm animals, and people, although there are complications associated with the various strategies for siRNA delivery including transgenesis. Alternative approaches could include using breeding or small molecule treatment to enhance the inherent antiviral capacity of infected cells.
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Affiliation(s)
- David C Baulcombe
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom;
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17
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Gong Q, Wang Y, Jin Z, Hong Y, Liu Y. Transcriptional and post-transcriptional regulation of RNAi-related gene expression during plant-virus interactions. STRESS BIOLOGY 2022; 2:33. [PMID: 37676459 PMCID: PMC10441928 DOI: 10.1007/s44154-022-00057-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 08/14/2022] [Indexed: 09/08/2023]
Abstract
As sessile organisms, plants encounter diverse invasions from pathogens including viruses. To survive and thrive, plants have evolved multilayered defense mechanisms to combat virus infection. RNAi, also known as RNA silencing, is an across-kingdom innate immunity and gene regulatory machinery. Molecular framework and crucial roles of RNAi in antiviral defense have been well-characterized. However, it is largely unknown that how RNAi is transcriptionally regulated to initiate, maintain and enhance cellular silencing under normal or stress conditions. Recently, insights into the transcriptional and post-transcriptional regulation of RNAi-related genes in different physiological processes have been emerging. In this review, we integrate these new findings to provide updated views on how plants modulate RNAi machinery at the (post-) transcriptional level to respond to virus infection.
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Affiliation(s)
- Qian Gong
- MOE Key Laboratory of Bioinformatics and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China
| | - Yunjing Wang
- MOE Key Laboratory of Bioinformatics and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China
| | - Zhenhui Jin
- Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
- School of Science and the Environment, University of Worcester, Worcester, WR2 6AJ, UK
| | - Yiguo Hong
- Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
- School of Science and the Environment, University of Worcester, Worcester, WR2 6AJ, UK
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Yule Liu
- MOE Key Laboratory of Bioinformatics and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China.
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18
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Wang Y, Liu H, Wang Z, Guo Y, Hu T, Zhou X. P25 and P37 proteins encoded by firespike leafroll-associated virus are viral suppressors of RNA silencing. Front Microbiol 2022; 13:964156. [PMID: 36051767 PMCID: PMC9424829 DOI: 10.3389/fmicb.2022.964156] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Firespike leafroll-associated virus (FLRaV) is a major pathogen associated with firespike (Odontonema tubaeforme) leafroll disease. Phylogenetic analysis showed that FLRaV possesses typical traits of subgroup II members of ampeloviruses, but encodes two additional proteins, P25 and P37. Here, we determined the microfilament localization of P25 protein. Posttranscriptional gene silencing (PTGS) assay showed that both FLRaV P25 and P37 were able to suppress the local and systemic PTGS and FLRaV P25 was capable of suppressing the green fluorescent protein (GFP) gene silencing triggered by both sense RNA-induced PTGS (S-PTGS) and inverted repeat RNA-induced PTGS (IR-PTGS). In contrast, FLRaV P37 was only able to inhibit the GFP silencing triggered by the S-PTGS but not the IR-PTGS. In the transcriptional gene silencing (TGS) assay, only FLRaV P25 was found to be able to reverse established TGS-mediated silencing of GFP in 16-TGS plants. We also found that FLRaV P25 could aggravate the disease symptom and viral titer of potato virus X in N. benthamiana. These results suggest that FLRaV P25 and P37 may have crucial roles in overcoming host RNA silencing, which provides key insights into our understanding of the molecular mechanisms underlying FLRaV infection.
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Affiliation(s)
- Yaqin Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Hui Liu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Zhanqi Wang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Sciences, Huzhou University, Huzhou, China
| | - Yushuang Guo
- Key Laboratory of Molecular Genetics, Guizhou Academy of Tobacco Science, Guiyang, China
| | - Tao Hu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- *Correspondence: Tao Hu,
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Xueping Zhou,
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19
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Shang K, Xu Y, Cao W, Xie X, Zhang Y, Zhang J, Liu H, Zhou S, Zhu X, Zhu C. Potato (Solanum tuberosum L.) non-specific lipid transfer protein StLTP6 promotes viral infection by inhibiting virus-induced RNA silencing. PLANTA 2022; 256:54. [PMID: 35927530 DOI: 10.1007/s00425-022-03948-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
For the first time it is reported that members of the nsLTP protein family could promote viral infection by inhibiting virus-induced RNA silencing. Non-specific lipid transfer proteins (nsLTPs) are a class of soluble proteins with low relative molecular weight and widely present in higher plants. The role of nsLTPs in biotic and abiotic stresses has been studied, but no report has shown that nsLTPs play a role in the process of viral infection. We report the function and mechanism of the classical nsLTP protein StLTP6 in viral infection. We found that StLTP6 expression was remarkably upregulated in potato infected with potato virus Y and potato virus S. The infection efficiency and virus content of StLTP6-overexpressed potato and Nicotiana benthamiana were remarkable increased. Further study found that the overexpression of StLTP6 inhibited the expression of multiple genes in the RNA silencing pathway, thereby inhibiting virus-induced RNA silencing. This result indicated that StLTP6 expression was induced during viral infection to inhibit the resistance of virus-induced RNA silencing and promote viral infection. In summary, we reported the role of StLTP6 in viral infection, broadening the biological function range of the nsLTP family and providing valuable information for the study of viral infection mechanism.
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Affiliation(s)
- Kaijie Shang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China
- College of Plant Protection, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Yang Xu
- Shandong Peanut Research Institute, Shandong Academy of Agricultural Sciences, Qingdao, 266100, China
| | - Weilin Cao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Xiaoying Xie
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Yanru Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Jingfeng Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Hongmei Liu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Shumei Zhou
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Xiaoping Zhu
- College of Plant Protection, Shandong Agricultural University, Tai'an, 271018, Shandong, China.
| | - Changxiang Zhu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China.
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20
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Ma J, Li C, Gao P, Qiu Y, Zong M, Zhang H, Wang J. Melon shoot organization 1, encoding an AGRONAUTE7 protein, plays a crucial role in plant development. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2022; 135:2875-2890. [PMID: 35802144 DOI: 10.1007/s00122-022-04156-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
A melon gene MSO1 located on chromosome 10 by map-based cloning strategy, which encodes an ARGONAUTE 7 protein, is responsible for the development of shoot organization. Plant endogenous small RNAs (sRNAs) are involved in various plant developmental processes. In Arabidopsis, sRNAs combined with ARGONAUTE (AGO) proteins are incorporated into the RNA-induced silencing complex (RISC), which functions in RNA silencing or biogenesis of trans-acting siRNAs (ta-siRNAs). However, their roles in melon (Cucumis melo L.) are still unclear. Here, the melon shoot organization 1 (mso1) mutant was identified and shown to exhibit pleiotropic phenotypes in leaf morphology and plant architecture. Positional cloning of MSO1 revealed that it encodes a homologue of Arabidopsis AGO7/ZIPPY, which is required for the production of ta-siRNAs. The AG-to-C mutation in the second exon of MSO1 caused a frameshift mutation and significantly reduced its expression. Ectopic expression of MSO1 rescued the Arabidopsis ago7 phenotype. RNA-seq analysis showed that several genes involved in transcriptional regulation and plant hormones were significantly altered in mso1 compared to WT. A total of 304 and 231 miRNAs were identified in mso1 and WT by sRNA sequencing, respectively, and among them, 42 known and ten novel miRNAs were differentially expressed. cme-miR390a significantly accumulated, and the expression levels of the two ta-siRNAs were almost completely abolished in mso1. Correspondingly, their targets, the ARF3 and ARF4 genes, showed dramatically upregulated expression, indicating that the miR390-TAS3-ARF pathway has conserved roles in melon. These findings will help us better understand the molecular mechanisms of MSO1 in plant development in melon.
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Affiliation(s)
- Jian Ma
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture and Rural Affairs, Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China.
| | - Congcong Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Peng Gao
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, Heilongjiang, China
| | - Yanhong Qiu
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture and Rural Affairs, Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Mei Zong
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture and Rural Affairs, Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Huijun Zhang
- School of Life Science, Huaibei Normal University, Huaibei, 235000, Anhui, China.
| | - Jianshe Wang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture and Rural Affairs, Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
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21
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Comparative Transcriptome Analysis of CMV or 2b-Deficient CMV-Infected dcl2dcl4 Reveals the Effects of Viral Infection on Symptom Induction in Arabidopsis thaliana. Viruses 2022; 14:v14071582. [PMID: 35891562 PMCID: PMC9320214 DOI: 10.3390/v14071582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 11/17/2022] Open
Abstract
Due to the impaired antiviral RNAi, the dcl2dcl4 (dcl2/4) mutant is highly susceptible to viruses deficient of the viral suppressor of the RNA silencing (VSR) contrast to wild-type Arabidopsis. It was found that more severe disease symptoms were induced in dcl2/4 infected with VSR-deficient CMV (CMV-Δ2b or CMV-2aTΔ2b) compared to wild-type Arabidopsis infected with intact CMV. In order to investigate the underlying mechanism, comparative transcriptome analysis was performed with Col-0 and dcl2/4 that were infected by CMV, CMV-Δ2b and CMV-2aTΔ2b, respectively. Our analysis showed that the systematic infection of CMV, CMV-Δ2b and CMV-2aTΔ2b could cause hypoxia response and reduce photosynthesis. Asymptomatic infections of CMV-Δ2b or CMV-2aTΔ2b in Columbia (Col-0) promoted the expression of cell division-related genes and suppressed the transcription of metabolism and acquired resistance genes. On the other hand, immunity and resistance genes were highly induced, but photosynthesis and polysaccharide metabolism-related genes were suppressed in diseased plants. More interestingly, cell wall reorganization was specifically caused in modestly diseased Col-0 infected by CMV and a strong activation of SA signaling were correspondingly induced in severely diseased dcl2/4 by CMV or CMV mutants. Thus, our research revealed the nature of the Arabidopsis–CMV interaction at the transcriptome level and could provide new clues in symptom development and antiviral defense in plants.
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22
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Rattan UK, Kumar S, Kumari R, Bharti M, Hallan V. Homeobox 27, a Homeodomain Transcription Factor, Confers Tolerances to CMV by Associating with Cucumber Mosaic Virus 2b Protein. Pathogens 2022; 11:pathogens11070788. [PMID: 35890032 PMCID: PMC9323240 DOI: 10.3390/pathogens11070788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/06/2022] [Accepted: 07/06/2022] [Indexed: 11/16/2022] Open
Abstract
Transcription factors (TFs) play an important role in plant development; however, their role during viral infection largely remains unknown. The present study was designed to uncover the role transcription factors play in Cucumber mosaic virus (CMV) infection. During the screening of an Arabidopsis thaliana (Col-0) transcription factor library, using the CMV 2b protein as bait in the yeast two-hybrid system, the 2b protein interacted with Homeobox protein 27 (HB27). HB27 belongs to the zinc finger homeodomain family and is known to have a regulatory role in flower development, and responses to biotic and abiotic stress. The interaction between CMV 2b and HB27 proteins was further validated using in planta (bimolecular fluorescence complementation assay) and in vitro far-Western blotting (FWB) methods. In the bimolecular fluorescence complementation assay, these proteins reconstituted YFP fluorescence in the nucleus and the cytoplasmic region as small fluorescent dots. In FWB, positive interaction was detected using bait anti-MYC antibody on the target HB27-HA protein. During CMV infection, upregulation (~3-fold) of the HB27 transcript was observed at 14 days post-infection (dpi) in A. thaliana plants, and expression declined to the same as healthy plants at 21 dpi. To understand the role of the HB27 protein during CMV infection, virus accumulation was determined in HB27-overexpressing (HB27 OE) and knockout mutants. In HB27-overexpressing lines, infected plants developed mild symptoms, accumulating a lower virus titer at 21 dpi compared to wild-type plants. Additionally, knockout HB27 mutants had more severe symptoms and a higher viral accumulation than wild-type plants. These results indicate that HB27 plays an important role in the regulation of plant defense against plant virus infection.
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Affiliation(s)
- Usha Kumari Rattan
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Surender Kumar
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
| | - Reenu Kumari
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
- College of Horticulture and Forestry, Dr. Y. S. Parmar University of Horticulture and Forestry, Thunag, Mandi 175048, India
| | - Monika Bharti
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
| | - Vipin Hallan
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Correspondence: ; Tel.: +91-1894-233338; Fax: +91-1894-230433
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23
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Shukla A, Hoffmann G, Kushwaha NK, López-González S, Hofius D, Hafrén A. Salicylic acid and the viral virulence factor 2b regulate the divergent roles of autophagy during cucumber mosaic virus infection. Autophagy 2022; 18:1450-1462. [PMID: 34740306 PMCID: PMC9225522 DOI: 10.1080/15548627.2021.1987674] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Macroautophagy/autophagy is a conserved intracellular degradation pathway that has recently emerged as an integral part of plant responses to virus infection. The known mechanisms of autophagy range from the selective degradation of viral components to a more general attenuation of disease symptoms. In addition, several viruses are able to manipulate the autophagy machinery and counteract autophagy-dependent resistance. Despite these findings, the complex interplay of autophagy activities, viral pathogenicity factors, and host defense pathways in disease development remains poorly understood. In the current study, we analyzed the interaction between autophagy and cucumber mosaic virus (CMV) in Arabidopsis thaliana. We show that autophagy is induced during CMV infection and promotes the turnover of the major virulence protein and RNA silencing suppressor 2b. Intriguingly, autophagy induction is mediated by salicylic acid (SA) and dampened by the CMV virulence factor 2b. In accordance with 2b degradation, we found that autophagy provides resistance against CMV by reducing viral RNA accumulation in an RNA silencing-dependent manner. Moreover, autophagy and RNA silencing attenuate while SA promotes CMV disease symptoms, and epistasis analysis suggests that autophagy-dependent disease and resistance are uncoupled. We propose that autophagy counteracts CMV virulence via both 2b degradation and reduced SA-responses, thereby increasing plant fitness with the viral trade-off arising from increased RNA silencing-mediated resistance.
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Affiliation(s)
- Aayushi Shukla
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
| | - Gesa Hoffmann
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
| | - Nirbhay Kumar Kushwaha
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
| | - Silvia López-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
| | - Daniel Hofius
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
| | - Anders Hafrén
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Box 7080, 75007Uppsala, Sweden
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Fan L, He C, Gao D, Xu T, Xing F, Yan J, Zhan B, Li S, Wang H. Identification of Silencing Suppressor Protein Encoded by Strawberry Mottle Virus. FRONTIERS IN PLANT SCIENCE 2022; 13:786489. [PMID: 35712581 PMCID: PMC9195133 DOI: 10.3389/fpls.2022.786489] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 04/29/2022] [Indexed: 06/15/2023]
Abstract
Strawberry mottle virus (SMoV) is associated with strawberry decline disease, causing losses to fruit yield and quality. In this study, using a screening system that enables detection of both local and systemic plant host (RNA silencing) defense responses, we found that Pro2Glu and P28, encoded by SMoV RNA2 genome, functioned to suppress local and systemic RNA silencing triggered by single- but not double-stranded GFP RNA. Subcellular localization assay revealed that both Pro2Glu and P28 were localized to nucleus and cytoplasm. The deletion of 11 amino acid residues at the C-terminus destabilized Pro2Glu protein, and the disruption of two conserved GW motifs deprived Pro2Glu of ability to suppress RNA silencing. Additionally, SMoV Pro2Glu and P28 enhanced the accumulation of potato virus X (PVX) in Nicotiana benthamiana 22 days post-infiltration, and P28 exacerbated significantly the symptoms of PVX. Collectively, these data indicate that the genome of SMoV RNA2 encodes two suppressors of RNA silencing. This is the first identification of a stramovirus suppressor of RNA silencing.
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Affiliation(s)
- Lingjiao Fan
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
| | - Chengyong He
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
| | - Dehang Gao
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
| | - Tengfei Xu
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
| | - Fei Xing
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiaqi Yan
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
| | - Binhui Zhan
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shifang Li
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hongqing Wang
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
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25
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Ray S, Casteel CL. Effector-mediated plant-virus-vector interactions. THE PLANT CELL 2022; 34:1514-1531. [PMID: 35277714 PMCID: PMC9048964 DOI: 10.1093/plcell/koac058] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 02/14/2022] [Indexed: 05/30/2023]
Abstract
Hemipterans (such as aphids, whiteflies, and leafhoppers) are some of the most devastating insect pests due to the numerous plant pathogens they transmit as vectors, which are primarily viral. Over the past decade, tremendous progress has been made in broadening our understanding of plant-virus-vector interactions, yet on the molecular level, viruses and vectors have typically been studied in isolation of each other until recently. From that work, it is clear that both hemipteran vectors and viruses use effectors to manipulate host physiology and successfully colonize a plant and that co-evolutionary dynamics have resulted in effective host immune responses, as well as diverse mechanisms of counterattack by both challengers. In this review, we focus on advances in effector-mediated plant-virus-vector interactions and the underlying mechanisms. We propose that molecular synergisms in vector-virus interactions occur in cases where both the virus and vector benefit from the interaction (mutualism). To support this view, we show that mutualisms are common in virus-vector interactions and that virus and vector effectors target conserved mechanisms of plant immunity, including plant transcription factors, and plant protein degradation pathways. Finally, we outline ways to identify true effector synergisms in the future and propose future research directions concerning the roles effectors play in plant-virus-vector interactions.
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Affiliation(s)
- Swayamjit Ray
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, New York 14850, USA
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26
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Urrutia CD, Romay G, Shaw BD, Verchot J. Advancing the Rose Rosette Virus Minireplicon and Encapsidation System by Incorporating GFP, Mutations, and the CMV 2b Silencing Suppressor. Viruses 2022; 14:836. [PMID: 35458566 PMCID: PMC9031449 DOI: 10.3390/v14040836] [Citation(s) in RCA: 3] [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: 02/16/2022] [Revised: 04/01/2022] [Accepted: 04/13/2022] [Indexed: 11/26/2022] Open
Abstract
Plant infecting emaraviruses have segmented negative strand RNA genomes and little is known about their infection cycles due to the lack of molecular tools for reverse genetic studies. Therefore, we innovated a rose rosette virus (RRV) minireplicon containing the green fluorescent protein (GFP) gene to study the molecular requirements for virus replication and encapsidation. Sequence comparisons among RRV isolates and structural modeling of the RNA dependent RNA polymerase (RdRp) and nucleocapsid (N) revealed three natural mutations of the type species isolate that we reverted to the common species sequences: (a) twenty-one amino acid truncations near the endonuclease domain (named delA), (b) five amino acid substitutions near the putative viral RNA binding loop (subT), and (c) four amino acid substitutions in N (NISE). The delA and subT in the RdRp influenced the levels of GFP, gRNA, and agRNA at 3 but not 5 days post inoculation (dpi), suggesting these sequences are essential for initiating RNA synthesis and replication. The NISE mutation led to sustained GFP, gRNA, and agRNA at 3 and 5 dpi indicating that the N supports continuous replication and GFP expression. Next, we showed that the cucumber mosaic virus (CMV strain FNY) 2b singularly enhanced GFP expression and RRV replication. Including agRNA2 with the RRV replicon produced observable virions. In this study we developed a robust reverse genetic system for investigations into RRV replication and virion assembly that could be a model for other emaravirus species.
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Affiliation(s)
| | | | | | - Jeanmarie Verchot
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77845, USA; (C.D.U.); (G.R.); (B.D.S.)
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27
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Xu Y, Ji X, Xu Z, Yuan Y, Chen X, Kong D, Zhang Y, Sun D. Transcriptome Profiling Reveals a Petunia Transcription Factor, PhCOL4, Contributing to Antiviral RNA Silencing. FRONTIERS IN PLANT SCIENCE 2022; 13:876428. [PMID: 35498675 PMCID: PMC9047179 DOI: 10.3389/fpls.2022.876428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/21/2022] [Indexed: 06/12/2023]
Abstract
RNA silencing is a common antiviral mechanism in eukaryotic organisms. However, the transcriptional regulatory mechanism that controls the RNA silencing process remains elusive. Here, we performed high-depth transcriptome analysis on petunia (Petunia hybrida) leaves infected with tobacco rattle virus (TRV) strain PPK20. A total of 7,402 differentially expressed genes (DEGs) were identified. Of them, some RNA silencing-related transcripts, such as RNA-dependent RNA polymerases (RDRs), Dicer-like RNase III enzymes (DCLs), and Argonautes (AGOs), were induced by viral attack. Furthermore, we performed TRV-based virus-induced gene silencing (VIGS) assay on 39 DEGs encoding putative transcription factors (TFs), using green fluorescent protein (GFP) and phytoene desaturase (PhPDS) as reporters. Results showed that the down-regulation of PhbHLH41, PhbHLH93, PhZPT4-3, PhCOL4, PhHSF-B3A, PhNAC90, and PhWRKY75 led to enhanced TRV accumulation and inhibited PhPDS-silenced photobleaching phenotype. In contrast, silencing of PhERF22 repressed virus accumulation and promoted photobleaching development. Thus, these TFs were identified as potential positive and negative regulators of antiviral RNA silencing, respectively. One positive regulator PhCOL4, belonging to the B-box zinc finger family, was selected for further functional characterization. Silencing and transient overexpression of PhCOL4 resulted in decreased and increased expression of several RNA silencing-related genes. DNA affinity purification sequencing analysis revealed that PhCOL4 targeted PhRDR6 and PhAGO4. Dual luciferase and yeast one-hybrid assays determined the binding of PhCOL4 to the PhRDR6 and PhAGO4 promoters. Our findings suggest that TRV-GFP-PhPDS-based VIGS could be helpful to identify transcriptional regulators of antiviral RNA silencing.
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Affiliation(s)
- Yingru Xu
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Xiaotong Ji
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Zhuangzhuang Xu
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Yanping Yuan
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Xiling Chen
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Derong Kong
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Yanlong Zhang
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
- National Engineering Technology Research Center for Oil Peony, Northwest A&F University, Yangling, China
| | - Daoyang Sun
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
- National Engineering Technology Research Center for Oil Peony, Northwest A&F University, Yangling, China
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28
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Ivanova Z, Minkov G, Gisel A, Yahubyan G, Minkov I, Toneva V, Baev V. The Multiverse of Plant Small RNAs: How Can We Explore It?
. Int J Mol Sci 2022; 23:ijms23073979. [PMID: 35409340 PMCID: PMC8999349 DOI: 10.3390/ijms23073979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/28/2022] [Accepted: 03/31/2022] [Indexed: 12/22/2022] Open
Abstract
Plant small RNAs (sRNAs) are a heterogeneous group of noncoding RNAs with a length of 20–24 nucleotides that are widely studied due to their importance as major regulators in various biological processes. sRNAs are divided into two main classes—microRNAs (miRNAs) and small interfering RNAs (siRNAs)—which differ in their biogenesis and functional pathways. Their identification and enrichment with new structural variants would not be possible without the use of various high-throughput sequencing (NGS) techniques, allowing for the detection of the total population of sRNAs in plants. Classifying sRNAs and predicting their functional role based on such high-performance datasets is a nontrivial bioinformatics task, as plants can generate millions of sRNAs from a variety of biosynthetic pathways. Over the years, many computing tools have been developed to meet this challenge. Here, we review more than 35 tools developed specifically for plant sRNAs over the past few years and explore some of their basic algorithms for performing tasks related to predicting, identifying, categorizing, and quantifying individual sRNAs in plant samples, as well as visualizing the results of these analyzes. We believe that this review will be practical for biologists who want to analyze their plant sRNA datasets but are overwhelmed by the number of tools available, thus answering the basic question of how to choose the right one for a particular study.
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Affiliation(s)
- Zdravka Ivanova
- Institute of Molecular Biology and Biotechnologies, 4108 Markovo, Bulgaria; (Z.I.); (G.M.); (I.M.); (V.T.)
| | - Georgi Minkov
- Institute of Molecular Biology and Biotechnologies, 4108 Markovo, Bulgaria; (Z.I.); (G.M.); (I.M.); (V.T.)
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria;
| | - Andreas Gisel
- Institute of Biomedical Technologies (ITB), CNR, 70126 Bari, Italy;
| | - Galina Yahubyan
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria;
| | - Ivan Minkov
- Institute of Molecular Biology and Biotechnologies, 4108 Markovo, Bulgaria; (Z.I.); (G.M.); (I.M.); (V.T.)
- Center of Plant System Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | - Valentina Toneva
- Institute of Molecular Biology and Biotechnologies, 4108 Markovo, Bulgaria; (Z.I.); (G.M.); (I.M.); (V.T.)
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria;
| | - Vesselin Baev
- Institute of Molecular Biology and Biotechnologies, 4108 Markovo, Bulgaria; (Z.I.); (G.M.); (I.M.); (V.T.)
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria;
- Correspondence:
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29
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Wang L, Yan X, Li Y, Wang Z, Chhajed S, Shang B, Wang Z, Choi SW, Zhao H, Chen S, Zhang X. PRP4KA phosphorylates SERRATE for degradation via 20 S proteasome to fine-tune miRNA production in Arabidopsis. SCIENCE ADVANCES 2022; 8:eabm8435. [PMID: 35333566 PMCID: PMC8956257 DOI: 10.1126/sciadv.abm8435] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Phosphorylation can quickly switch on/off protein functions. Here, we reported pre-mRNA processing 4 kinase A (PRP4KA), and its paralogs interact with Serrate (SE), a key factor in RNA processing. PRP4KA phosphorylates at least five residues of SE in vitro and in vivo. Hypophosphorylated, but not hyperphosphorylated, SE variants could readily rescue se phenotypes in vivo. Moreover, hypophosphorylated SE variants had stronger binding affinity to microprocessor component HYL1 and were more resistant to degradation by 20S proteasome than hyperphosphorylated counterparts. Knockdown of the kinases enhanced the accumulation of hypophosphorylated SE. However, the excessive SE interfered with the assembly and function of SE-scaffolded macromolecule complexes, causing the se-like defects in the mutant and wild-type backgrounds. Thus, phosphorylation of SE via PRP4KA can quickly clear accumulated SE to secure its proper amount. This study provides new insight into how protein phosphorylation regulates miRNA metabolism through controlling homeostasis of SE accumulation in plants.
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Affiliation(s)
- Lin Wang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Laboratory of Bio-interactions and Crop Health, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Xingxing Yan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Yanjun Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Zhiye Wang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Shweta Chhajed
- Department of Biology, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida, Gainesville, FL 32610, USA
| | - Baoshuan Shang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Zhen Wang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Suk Won Choi
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Hongwei Zhao
- Laboratory of Bio-interactions and Crop Health, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Sixue Chen
- Department of Biology, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida, Gainesville, FL 32610, USA
| | - Xiuren Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
- Corresponding author.
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30
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Karimi K, Sadeghi A, Maroufpoor M, Azizi A. Induction of resistance to Myzus persicae-nicotianae in Cucumber mosaic virus infected tobacco plants using silencing of CMV-2b gene. Sci Rep 2022; 12:4096. [PMID: 35260757 PMCID: PMC8904847 DOI: 10.1038/s41598-022-08202-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 03/04/2022] [Indexed: 11/25/2022] Open
Abstract
Aphids such as tobacco aphid Myzus persicae-nicotianae, are among the most important plant viral vectors and plant viruses encode genes to interact with their vectors. Cucumber mosaic virus (CMV) encodes 2b protein as a suppressor of plant immune and it plays a vital role in CMV accumulation and susceptibility to aphid vectors. In this study, the resistance of tobacco plants (Nicotiana tabacum) to M. p. nicotianae was evaluated by silencing of 2b in CMV-infected plants. However, the pFGC-C.h silencing gene construct was transiently expressed using Agrobacterium tumefacience, LBA 4404 in tobacco leaves, and four days later, the plants were mechanically inoculated by CMV (Kurdistan isolate), and then, 15 days post-inoculation 1 nonviruliferous aphid was placed on each leaf for evaluation of resistance to M. p. nicotianae. To evaluate the tobacco plants resistance and susceptibility to M. p. nicotianae, the number of aphids existent per tobacco leaf, life table and, demographic parameters were recorded and used as a comparison indicator. The obtained results were analyzed using the age-stage, two-sex life table. The highest number of aphids was recorded on the control CMV-infected plants, while the lowest number on CMV infected leaves expressing CMV-2b silencing construct (pFGC-C.h). The obtained data revealed the lowest rate for all of intrinsic rate of natural increase (rm) (0.246/day), the rate of reproduction (r0) (17.04 females/generation), and finite rate of increase (λ) (1.279/day), on the pFGC-C.h treatment. The maximum generation time (T) (11.834 days) was observed on (V) treatment. However, the collected data revealed induction of resistance to tobacco aphids by silencing of CMV-2b in CMV infected plants.
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Affiliation(s)
- Kazhal Karimi
- Department of Plant Protection, University of Kurdistan, Sanandaj, Iran
| | - Amin Sadeghi
- Department of Plant Protection, University of Kurdistan, Sanandaj, Iran.
| | | | - Abdolbaset Azizi
- Department of Plant Protection, University of Kurdistan, Sanandaj, Iran.
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31
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Jin L, Chen M, Xiang M, Guo Z. RNAi-Based Antiviral Innate Immunity in Plants. Viruses 2022; 14:v14020432. [PMID: 35216025 PMCID: PMC8875485 DOI: 10.3390/v14020432] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 12/13/2022] Open
Abstract
Multiple antiviral immunities were developed to defend against viral infection in hosts. RNA interference (RNAi)-based antiviral innate immunity is evolutionarily conserved in eukaryotes and plays a vital role against all types of viruses. During the arms race between the host and virus, many viruses evolve viral suppressors of RNA silencing (VSRs) to inhibit antiviral innate immunity. Here, we reviewed the mechanism at different stages in RNAi-based antiviral innate immunity in plants and the counteractions of various VSRs, mainly upon infection of RNA viruses in model plant Arabidopsis. Some critical challenges in the field were also proposed, and we think that further elucidating conserved antiviral innate immunity may convey a broad spectrum of antiviral strategies to prevent viral diseases in the future.
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32
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Wang D, Dawadi B, Qu J, Ye J. Light-Engineering Technology for Enhancing Plant Disease Resistance. FRONTIERS IN PLANT SCIENCE 2022; 12:805614. [PMID: 35251062 PMCID: PMC8891579 DOI: 10.3389/fpls.2021.805614] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 12/31/2021] [Indexed: 06/14/2023]
Abstract
Insect vector-borne diseases are a major constraint to a wide variety of crops. Plants integrate environmental light and internal signalings to defend dual stresses both from the vector insects and vector-transmitted pathogens. In this review, we highlight a studies that demonstrate how light regulates plants deploying mechanisms against vector-borne diseases. Four major host defensive pathways involved in the host defense network against multiple biotic stresses are reviewed: innate immunity, phytohormone signaling, RNA interference, and protein degradation. The potential with light-engineering technology with light emitting diodes (LEDs) and genome engineering technology for fine-tuning crop defense and yield are also discussed.
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Affiliation(s)
- Duan Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Bishnu Dawadi
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Jing Qu
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
- Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China
| | - Jian Ye
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
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33
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Murai H, Atsumaru K, Mochizuki T. Effect of mutations in the 2b protein of tomato aspermy virus on RNA silencing suppressor activity, virulence, and virus-induced gene silencing. Arch Virol 2022; 167:471-481. [PMID: 34978608 DOI: 10.1007/s00705-021-05344-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/15/2021] [Indexed: 11/25/2022]
Abstract
Tomato aspermy virus (TAV) and cucumber mosaic virus (CMV) belong to the genus Cucumovirus in the family Bromoviridae. The cucumovirus 2b protein is one of the first identified viral suppressors of RNA silencing (VSR). The cucumovirus 2b protein contains a conserved amino acid motif consisting of several highly conserved amino acid residues. Here, we demonstrate that the TAV 2b protein N-terminal region, Arg46, Ser40, and Ser42 as well as the CMV 2b protein are essential for VSR activity, virulence, and viral RNA accumulation. Furthermore, we developed the first TAV-induced gene silencing (VIGS) vector. In contrast to other cucumovirus vectors, such as CMV and peanut stunt virus, the TAV vector did not induce a silencing phenotype in Nicotiana benthamiana when 2b protein VSR activity was retained. These findings suggest that the cucumovirus 2b proteins share amino acid residues for VSR activity but may have different roles in VIGS induction.
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Affiliation(s)
- Hirotomo Murai
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
| | - Kenta Atsumaru
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
| | - Tomofumi Mochizuki
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan.
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34
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Zhou J, Zhang R, Jia X, Tang X, Guo Y, Yang H, Zheng X, Qian Q, Qi Y, Zhang Y. CRISPR-Cas9 mediated OsMIR168a knockout reveals its pleiotropy in rice. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:310-322. [PMID: 34555252 PMCID: PMC8753357 DOI: 10.1111/pbi.13713] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/31/2021] [Accepted: 09/15/2021] [Indexed: 05/21/2023]
Abstract
MicroRNA168 (MIR168) is a key miRNA that targets the main RNA-induced silencing complex component Argonaute 1 (AGO1) to regulate plant growth and environmental stress responses. However, the regulatory functions of MIR168 need to be further elucidated in rice. In this paper, we generated clean OsMIR168a deletion mutants by CRISPR-Cas9 strategy. We then phenotypically and molecularly characterized these mutants. The rice OsMIR168a mutants grew rapidly at the seedling stage, produced more tillers and matured early. Compared to the wild-type plants, the mutants were shorter at maturity and produced smaller spikelets and seeds. Analysis of gene expression showed that the transcription levels of OsMIR168a's target genes such as OsAGO1a, OsAGO1b and OsAGO1d were elevated significantly in the OsMIR168a mutants. Intriguingly, OsAGO18, a member of a new AGO clade that is conserved in monocots, was confirmed to be a target of OsMIR168a not only by informatic prediction but also by expression analysis and a cell-based cleavage assay in the OsMIR168a mutants. Many protein-coding genes and miRNAs showed differential expression in the OsMIR168a mutants, suggesting OsMIR168a exerts a major transcriptional regulatory role, likely through its potential target genes such as OsAGO1s and OsAGO18. KEGG enrichment analysis of these differentially expressed genes pointed to OsMIR168a's involvement in important processes such as plant hormone signalling transduction and plant-pathogen interaction. These data collectively support that the complex regulation module of OsMIR168a-OsAGO1/OsAGO18-miRNAs-target genes contributes to agronomically important traits, which sheds light on miRNA-mediated crop breeding.
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Affiliation(s)
- Jianping Zhou
- Department of BiotechnologySchool of Life Sciences and TechnologyCenter for Informational BiologyUniversity of Electronic Science and Technology of ChinaChengduChina
| | - Rui Zhang
- Department of BiotechnologySchool of Life Sciences and TechnologyCenter for Informational BiologyUniversity of Electronic Science and Technology of ChinaChengduChina
| | - Xinyu Jia
- Department of BiotechnologySchool of Life Sciences and TechnologyCenter for Informational BiologyUniversity of Electronic Science and Technology of ChinaChengduChina
| | - Xu Tang
- Department of BiotechnologySchool of Life Sciences and TechnologyCenter for Informational BiologyUniversity of Electronic Science and Technology of ChinaChengduChina
- State Key Laboratory of Rice BiologyChina National Rice Research InstituteHangzhouChina
| | - Yachong Guo
- Department of BiotechnologySchool of Life Sciences and TechnologyCenter for Informational BiologyUniversity of Electronic Science and Technology of ChinaChengduChina
| | - Han Yang
- Department of BiotechnologySchool of Life Sciences and TechnologyCenter for Informational BiologyUniversity of Electronic Science and Technology of ChinaChengduChina
| | - Xuelian Zheng
- Department of BiotechnologySchool of Life Sciences and TechnologyCenter for Informational BiologyUniversity of Electronic Science and Technology of ChinaChengduChina
| | - Qian Qian
- State Key Laboratory of Rice BiologyChina National Rice Research InstituteHangzhouChina
| | - Yiping Qi
- Department of Plant Science and Landscape ArchitectureUniversity of MarylandCollege ParkMDUSA
- Institute for Bioscience and Biotechnology ResearchUniversity of MarylandRockvilleMDUSA
| | - Yong Zhang
- Department of BiotechnologySchool of Life Sciences and TechnologyCenter for Informational BiologyUniversity of Electronic Science and Technology of ChinaChengduChina
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Yu Y, Gui Y, Li Z, Jiang C, Guo J, Niu D. Induced Systemic Resistance for Improving Plant Immunity by Beneficial Microbes. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11030386. [PMID: 35161366 PMCID: PMC8839143 DOI: 10.3390/plants11030386] [Citation(s) in RCA: 96] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 05/05/2023]
Abstract
Plant beneficial microorganisms improve the health and growth of the associated plants. Application of beneficial microbes triggers an enhanced resistance state, also termed as induced systemic resistance (ISR), in the host, against a broad range of pathogens. Upon the activation of ISR, plants employ long-distance systemic signaling to provide protection for distal tissue, inducing rapid and strong immune responses against pathogens invasions. The transmission of ISR signaling was commonly regarded to be a jasmonic acid- and ethylene-dependent, but salicylic acid-independent, transmission. However, in the last decade, the involvement of both salicylic acid and jasmonic acid/ethylene signaling pathways and the regulatory roles of small RNA in ISR has been updated. In this review, the plant early recognition, responsive reactions, and the related signaling transduction during the process of the plant-beneficial microbe interaction was discussed, with reflection on the crucial regulatory role of small RNAs in the beneficial microbe-mediated ISR.
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Affiliation(s)
- Yiyang Yu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Y.Y.); (Y.G.); (Z.L.); (C.J.); (J.G.)
- State Key Laboratory of Biological Interactions and Crop Health, Nanjing Agricultural University, Nanjing 210095, China
- Engineering Center of Bioresource Pesticide in Jiangsu Province, Nanjing 210095, China
| | - Ying Gui
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Y.Y.); (Y.G.); (Z.L.); (C.J.); (J.G.)
- State Key Laboratory of Biological Interactions and Crop Health, Nanjing Agricultural University, Nanjing 210095, China
- Engineering Center of Bioresource Pesticide in Jiangsu Province, Nanjing 210095, China
| | - Zijie Li
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Y.Y.); (Y.G.); (Z.L.); (C.J.); (J.G.)
- State Key Laboratory of Biological Interactions and Crop Health, Nanjing Agricultural University, Nanjing 210095, China
- Engineering Center of Bioresource Pesticide in Jiangsu Province, Nanjing 210095, China
| | - Chunhao Jiang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Y.Y.); (Y.G.); (Z.L.); (C.J.); (J.G.)
- State Key Laboratory of Biological Interactions and Crop Health, Nanjing Agricultural University, Nanjing 210095, China
- Engineering Center of Bioresource Pesticide in Jiangsu Province, Nanjing 210095, China
| | - Jianhua Guo
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Y.Y.); (Y.G.); (Z.L.); (C.J.); (J.G.)
- State Key Laboratory of Biological Interactions and Crop Health, Nanjing Agricultural University, Nanjing 210095, China
- Engineering Center of Bioresource Pesticide in Jiangsu Province, Nanjing 210095, China
| | - Dongdong Niu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Y.Y.); (Y.G.); (Z.L.); (C.J.); (J.G.)
- State Key Laboratory of Biological Interactions and Crop Health, Nanjing Agricultural University, Nanjing 210095, China
- Engineering Center of Bioresource Pesticide in Jiangsu Province, Nanjing 210095, China
- Correspondence:
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Small RNAs Participate in Plant-Virus Interaction and Their Application in Plant Viral Defense. Int J Mol Sci 2022; 23:ijms23020696. [PMID: 35054880 PMCID: PMC8775341 DOI: 10.3390/ijms23020696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/30/2021] [Accepted: 01/05/2022] [Indexed: 02/06/2023] Open
Abstract
Small RNAs are significant regulators of gene expression, which play multiple roles in plant development, growth, reproductive and stress response. It is generally believed that the regulation of plants’ endogenous genes by small RNAs has evolved from a cellular defense mechanism for RNA viruses and transposons. Most small RNAs have well-established roles in the defense response, such as viral response. During viral infection, plant endogenous small RNAs can direct virus resistance by regulating the gene expression in the host defense pathway, while the small RNAs derived from viruses are the core of the conserved and effective RNAi resistance mechanism. As a counter strategy, viruses evolve suppressors of the RNAi pathway to disrupt host plant silencing against viruses. Currently, several studies have been published elucidating the mechanisms by which small RNAs regulate viral defense in different crops. This paper reviews the distinct pathways of small RNAs biogenesis and the molecular mechanisms of small RNAs mediating antiviral immunity in plants, as well as summarizes the coping strategies used by viruses to override this immune response. Finally, we discuss the current development state of the new applications in virus defense based on small RNA silencing.
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Takahashi H, Tabara M, Miyashita S, Ando S, Kawano S, Kanayama Y, Fukuhara T, Kormelink R. Cucumber Mosaic Virus Infection in Arabidopsis: A Conditional Mutualistic Symbiont? Front Microbiol 2022; 12:770925. [PMID: 35069476 PMCID: PMC8776717 DOI: 10.3389/fmicb.2021.770925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 12/02/2021] [Indexed: 11/13/2022] Open
Abstract
A cucumber mosaic virus isolate, named Ho [CMV(Ho)], was isolated from a symptomless Arabidopsis halleri field sample containing low virus titers. An analysis of CMV(Ho) RNA molecules indicated that the virus isolate, besides the usual cucumovirus tripartite RNA genome, additionally contained defective RNA3 molecules and a satellite RNA. To study the underlying mechanism of the persistent CMV(Ho) infection in perennial A. halleri, infectious cDNA clones were generated for all its genetic elements. CMV, which consists of synthetic transcripts from the infectious tripartite RNA genomes, and designated CMV(Ho)tr, multiplied in A. halleri and annual Arabidopsis thaliana Col-0 to a similar level as the virulent strain CMV(Y), but did not induce any symptoms in them. The response of Col-0 to a series of reassortant CMVs between CMV(Ho)tr and CMV(Y) suggested that the establishment of an asymptomatic phenotype of CMV(Ho) infection was due to the 2b gene of CMV RNA2, but not due to the presence of the defective RNA3 and satellite RNA. The accumulation of CMV(Ho) 2b protein tagged with the FLAG epitope (2b.Ho-FLAG) in 2b.Ho-FLAG-transformed Col-0 did not induce any symptoms, suggesting a 2b-dependent persistency of CMV(Ho)tr infection in Arabidopsis. The 2b protein interacted with Argonaute 4, which is known to regulate the cytosine methylation levels of host genomic DNA. Whole genomic bisulfite sequencing analysis of CMV(Ho)tr- and mock-inoculated Col-0 revealed that cytosine hypomethylation in the promoter regions of 82 genes, including two genes encoding transcriptional regulators (DOF1.7 and CBP1), was induced in response to CMV(Ho)tr infection. Moreover, the increased levels of hypomethylation in the promoter region of both genes, during CMV(Ho)tr infection, were correlated with the up- or down-regulation of their expression. Taken altogether, the results indicate that during persistent CMV(Ho) infection in Arabidopsis, host gene expression may be epigenetically modulated resulting from a 2b-mediated cytosine hypomethylation of host genomic DNA.
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Affiliation(s)
- Hideki Takahashi
- Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Midori Tabara
- Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, Fuchu, Japan
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Kusatsu, Japan
| | - Shuhei Miyashita
- Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Sugihiro Ando
- Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Shuichi Kawano
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Japan
| | - Yoshinori Kanayama
- Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Toshiyuki Fukuhara
- Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Richard Kormelink
- Laboratory of Virology, Department of Plant Sciences, Wageningen University and Research, Wageningen, Netherlands
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Marttinen EM, Lehtonen MT, van Gessel N, Reski R, Valkonen JPT. Viral suppressor of RNA silencing in vascular plants also interferes with the development of the bryophyte Physcomitrella patens. PLANT, CELL & ENVIRONMENT 2022; 45:220-235. [PMID: 34564869 PMCID: PMC9135061 DOI: 10.1111/pce.14194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
Plant viruses are important pathogens able to overcome plant defense mechanisms using their viral suppressors of RNA silencing (VSR). Small RNA pathways of bryophytes and vascular plants have significant similarities, but little is known about how viruses interact with mosses. This study elucidated the responses of Physcomitrella patens to two different VSRs. We transformed P. patens plants to express VSR P19 from tomato bushy stunt virus and VSR 2b from cucumber mosaic virus, respectively. RNA sequencing and quantitative PCR were used to detect the effects of VSRs on gene expression. Small RNA (sRNA) sequencing was used to estimate the influences of VSRs on the sRNA pool of P. patens. Expression of either VSR-encoding gene caused developmental disorders in P. patens. The transcripts of four different transcription factors (AP2/erf, EREB-11 and two MYBs) accumulated in the P19 lines. sRNA sequencing revealed that VSR P19 significantly changed the microRNA pool in P. patens. Our results suggest that VSR P19 is functional in P. patens and affects the abundance of specific microRNAs interfering with gene expression. The results open new opportunities for using Physcomitrella as an alternative system to study plant-virus interactions.
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Affiliation(s)
- Eeva M. Marttinen
- Department of Agricultural SciencesUniversity of HelsinkiHelsinkiFinland
| | - Mikko T. Lehtonen
- Department of Agricultural SciencesUniversity of HelsinkiHelsinkiFinland
- Plant Analytics UnitFinnish Food AuthorityHelsinkiFinland
| | - Nico van Gessel
- Plant Biotechnology, Faculty of BiologyUniversity of FreiburgFreiburgGermany
| | - Ralf Reski
- Plant Biotechnology, Faculty of BiologyUniversity of FreiburgFreiburgGermany
- Signalling Research Centres BIOSS and CIBSSUniversity of FreiburgFreiburgGermany
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Importin/exportin-mediated nucleocytoplasmic shuttling of cucumber mosaic virus 2b protein is required for 2b's efficient suppression of RNA silencing. PLoS Pathog 2022; 18:e1010267. [PMID: 35081172 PMCID: PMC8820599 DOI: 10.1371/journal.ppat.1010267] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 02/07/2022] [Accepted: 01/11/2022] [Indexed: 11/19/2022] Open
Abstract
The 2b protein (2b) of cucumber mosaic virus (CMV), an RNA-silencing suppressor (RSS), is a major pathogenicity determinant of CMV. 2b is localized in the nucleus and cytoplasm, and its nuclear import is determined by two nuclear localization signals (NLSs); a carrier protein (importin [IMPα]) is predicted to be involved in 2b's nuclear transport. Cytoplasmic 2bs play a role in suppression of RNA silencing by binding to small RNAs and AGO proteins. A putative nuclear export signal (NES) motif was also found in 2b, but has not been proved to function. Here, we identified a leucine-rich motif in 2b's C-terminal half as an NES. We then showed that NES-deficient 2b accumulated abundantly in the nucleus and lost its RSS activity, suggesting that 2b exported from the nucleus can play a role as an RSS. Although two serine residues (S40 and S42) were previously found to be phosphorylated, we also found that an additional phosphorylation site (S28) alone can affect 2b's nuclear localization and RSS activity. Alanine substitution at S28 impaired the IMPα-mediated nuclear/nucleolar localization of 2b, and RSS activity was even stronger compared to wild-type 2b. In a subcellular fractionation assay, phosphorylated 2bs were detected in the nucleus, and comparison of the accumulation levels of nuclear phospho-2b between wild-type 2b and the NES mutant showed a greatly reduced level of the phosphorylated NES mutant in the nucleus, suggesting that 2bs are dephosphorylated in the nucleus and may be translocated to the cytoplasm in a nonphosphorylated form. These results suggest that 2b manipulates its nucleocytoplasmic transport as if it tracks down its targets, small RNAs and AGOs, in the RNA silencing pathway. We infer that 2b's efficient RSS activity is maintained by a balance of phosphorylation and dephosphorylation, which are coupled to importin/exportin-mediated shuttling between the nucleus and cytoplasm.
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40
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Pantaleo V, Masuta C. Diversity of viral RNA silencing suppressors and their involvement in virus-specific symptoms. Adv Virus Res 2022; 113:1-23. [DOI: 10.1016/bs.aivir.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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41
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Annacondia ML, Martinez G. Reprogramming of RNA silencing triggered by cucumber mosaic virus infection in Arabidopsis. Genome Biol 2021; 22:340. [PMID: 34911561 PMCID: PMC8672585 DOI: 10.1186/s13059-021-02564-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 12/02/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND RNA silencing has an important role mediating sequence-specific virus resistance in plants. The complex interaction of viruses with RNA silencing involves the loading of viral small interfering RNAs (vsiRNAs) into its host ARGONAUTE (AGO) proteins. As a side effect of their antiviral activity, vsiRNAs loading into AGO proteins can also mediate the silencing of endogenous genes. Here, we analyze at the genome-wide level both aspects of the interference of cucumber mosaic virus (CMV) with the RNA silencing machinery of Arabidopsis thaliana. RESULTS We observe CMV-derived vsiRNAs affect the levels of endogenous sRNA classes. Furthermore, we analyze the incorporation of vsiRNAs into AGO proteins with a described antiviral role and the viral suppressor of RNA silencing (VSR) 2b, by combining protein immunoprecipitation with sRNA high-throughput sequencing. Interestingly, vsiRNAs represent a substantial percentage of AGO-loaded sRNAs and displace other endogenous sRNAs. As a countermeasure, the VSR 2b loaded vsiRNAs and mRNA-derived siRNAs, which affect the expression of the genes they derive from. Additionally, we analyze how vsiRNAs incorporate into the endogenous RNA silencing pathways by exploring their target mRNAs using parallel analysis of RNA end (PARE) sequencing, which allow us to identify vsiRNA-targeted genes genome-wide. CONCLUSIONS This work exemplifies the complex relationship of RNA viruses with the endogenous RNA silencing machinery and the multiple aspects of virus resistance and virulence that this interaction induces.
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Affiliation(s)
- Maria Luz Annacondia
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - German Martinez
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden.
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Miao S, Liang C, Li J, Baker B, Luo L. Polycistronic Artificial microRNA-Mediated Resistance to Cucumber Green Mottle Mosaic Virus in Cucumber. Int J Mol Sci 2021; 22:ijms222212237. [PMID: 34830122 PMCID: PMC8620374 DOI: 10.3390/ijms222212237] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/17/2022] Open
Abstract
Cucumber green mottle mosaic virus (CGMMV), as a typical seed-borne virus, causes costly and devastating diseases in the vegetable trade worldwide. Genetic sources for resistance to CGMMV in cucurbits are limited, and environmentally safe approaches for curbing the accumulation and spread of seed-transmitted viruses and cultivating completely resistant plants are needed. Here, we describe the design and application of RNA interference-based technologies, containing artificial microRNA (amiRNA) and synthetic trans-acting small interfering RNA (syn-tasiRNA), against conserved regions of different strains of the CGMMV genome. We used a rapid transient sensor system to identify effective anti-CGMMV amiRNAs. A virus seed transmission assay was developed, showing that the externally added polycistronic amiRNA and syn-tasiRNA can successfully block the accumulation of CGMMV in cucumber, but different virulent strains exhibited distinct influences on the expression of amiRNA due to the activity of the RNA-silencing suppressor. We also established stable transgenic cucumber plants expressing polycistronic amiRNA, which conferred disease resistance against CGMMV, and no sequence mutation was observed in CGMMV. This study demonstrates that RNA interference-based technologies can effectively prevent the occurrence and accumulation of CGMMV. The results provide a basis to establish and fine-tune approaches to prevent and treat seed-based transmission viral infections.
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Affiliation(s)
- Shuo Miao
- College of Plant Protection, China Agricultural University, Beijing 100193, China; (S.M.); (J.L.)
- Beijing Key Laboratory of Seed Disease Testing and Control, China Agricultural University, Beijing 100193, China
| | | | - Jianqiang Li
- College of Plant Protection, China Agricultural University, Beijing 100193, China; (S.M.); (J.L.)
- Beijing Key Laboratory of Seed Disease Testing and Control, China Agricultural University, Beijing 100193, China
| | - Barbara Baker
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Plant Gene Expression Center, United States Department of Agriculture-Agricultural Research Service, Albany, CA 94710, USA
- Correspondence: (B.B.); (L.L.)
| | - Laixin Luo
- College of Plant Protection, China Agricultural University, Beijing 100193, China; (S.M.); (J.L.)
- Beijing Key Laboratory of Seed Disease Testing and Control, China Agricultural University, Beijing 100193, China
- Correspondence: (B.B.); (L.L.)
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Gao Y, Yang J, Zhang X, Chen A, Gu Z, Du Z. The Weak Small RNA-Binding Activity of the 2b Proteins of Subgroup II Cucumber Mosaic Virus Strains Is Insufficient for RNA Silencing Suppression. Front Microbiol 2021; 12:760937. [PMID: 34745069 PMCID: PMC8569468 DOI: 10.3389/fmicb.2021.760937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 09/15/2021] [Indexed: 11/13/2022] Open
Abstract
The 2b proteins encoded by cucumber mosaic virus (CMV) subgroup I strains suppress RNA silencing primarily by competitively binding small RNAs (sRNAs) in the host cell cytoplasm. Interestingly, 2b proteins encoded by CMV subgroup II strains accumulate predominantly in nuclei. Here we determined that whereas the 2b protein (Fny2b) of subgroup IA strain Fny-CMV is highly effective in suppressing both sense RNA-induced and inverted repeat-induced posttranscriptional gene silencing, the 2b protein (LS2b) of the subgroup II strain LS-CMV was not as effective. Reducing nuclear accumulation of LS2b by mutating a residue in its nuclear localization sequence had no effect on RNA silencing suppressor activity, while attenuated viral symptoms. Electrophoretic mobility shift assays showed that the sRNA binding of LS2b was weaker and more selective than that of Fny2b. The domain determining the differential sRNA-binding ability was delimited to the putative helix α1 region. Moreover, LS2b mutants that completely lost suppressor activity still retained their weak sRNA-binding ability, suggesting that sRNA binding is not sufficient for LS2b to suppress RNA silencing. Considering the subgroup I strain-encoded 2b proteins that require sRNA-binding ability for the suppression of RNA silencing, we suggest that in addition to binding sRNA, the 2b proteins of subgroup II CMV strains would require extra biological activities to achieve RNA silencing inhibition.
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Affiliation(s)
- Yingying Gao
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Jinrui Yang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Xiaobei Zhang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Aizhong Chen
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Zhouhang Gu
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Zhiyou Du
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
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Kumari R, Kumar S, Leibman D, Abebie B, Shnaider Y, Ding S, Gal‐On A. Cucumber RDR1s and cucumber mosaic virus suppressor protein 2b association directs host defence in cucumber plants. MOLECULAR PLANT PATHOLOGY 2021; 22:1317-1331. [PMID: 34355485 PMCID: PMC8518566 DOI: 10.1111/mpp.13112] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/03/2021] [Accepted: 07/05/2021] [Indexed: 05/27/2023]
Abstract
RNA-dependent RNA polymerases (RDRs) regulate important aspects of plant development and resistance to pathogens. The role of RDRs in virus resistance has been demonstrated using siRNA signal amplification and through the methylation of viral genomes. Cucumber (Cucumis sativus) has four RDR1 genes that are differentially induced during virus infection: CsRDR1a, CsRDR1b, and duplicated CsRDR1c1/c2. The mode of action of CsRDR1s during viral infection is unknown. Transient expression of the cucumber mosaic virus (CMV)-2b protein (the viral suppressor of RNA silencing) in cucumber protoplasts induced the expression of CsRDR1c, but not of CsRDR1a/1b. Results from the yeast two-hybrid system showed that CsRDR1 proteins interacted with CMV-2b and this was confirmed by bimolecular fluorescence complementation assays. In protoplasts, CsRDR1s localized in the cytoplasm as punctate spots. Colocalization experiments revealed that CsRDR1s and CMV-2b were uniformly dispersed throughout the cytoplasm, suggesting that CsRDR1s are redistributed as a result of interactions. Transient overexpression of individual CsRDR1a/1b genes in protoplasts reduced CMV accumulation, indicating their antiviral role. However, overexpression of CsRDR1c in protoplasts resulted in relatively higher accumulation of CMV and CMVΔ2b. In single cells, CsRDR1c enhances viral replication, leading to CMV accumulation and blocking secondary siRNA amplification of CsRDR1c by CMV-2b protein. This suggests that CMV-2b acts as both a transcription factor that induces CsRDR1c (controlling virus accumulation) and a suppressor of CsRDR1c activity.
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Affiliation(s)
- Reenu Kumari
- Department of Plant Pathology and Weed ResearchAgricultural Research OrganizationRishon LeZionIsrael
- College of Horticulture and ForestryDr YS Parmar University of Horticulture and ForestryMandiIndia
| | - Surender Kumar
- Department of Plant Pathology and Weed ResearchAgricultural Research OrganizationRishon LeZionIsrael
- Plant Virology Lab, Biotechnology DivisionCSIR‐Institute of Himalayan Bioresource TechnologyPalampurIndia
| | - Diana Leibman
- Department of Plant Pathology and Weed ResearchAgricultural Research OrganizationRishon LeZionIsrael
| | - Bekele Abebie
- Department of Plant Pathology and Weed ResearchAgricultural Research OrganizationRishon LeZionIsrael
| | - Yulia Shnaider
- Department of Plant Pathology and Weed ResearchAgricultural Research OrganizationRishon LeZionIsrael
| | - Shou‐Wei Ding
- Department of Plant Pathology and Microbiology & Institute for Integrative Genome BiologyUniversity of CaliforniaRiversideCaliforniaUSA
| | - Amit Gal‐On
- Department of Plant Pathology and Weed ResearchAgricultural Research OrganizationRishon LeZionIsrael
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45
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Tarquini G, Pagliari L, Ermacora P, Musetti R, Firrao G. Trigger and Suppression of Antiviral Defenses by Grapevine Pinot Gris Virus (GPGV): Novel Insights into Virus-Host Interaction. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1010-1023. [PMID: 33983824 DOI: 10.1094/mpmi-04-21-0078-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Grapevine Pinot gris virus (GPGV) is an emerging trichovirus that has been putatively associated with a novel grapevine disease known as grapevine leaf mottling and deformation (GLMD). Yet the role of GPGV in GLMD disease is poorly understood, since it has been detected both in symptomatic and symptomless grapevines. We exploited a recently constructed GPGV infectious clone (pRI::GPGV-vir) to induce an antiviral response in Nicotiana benthamiana plants. In silico prediction of virus-derived small interfering RNAs and gene expression analyses revealed the involvement of DCL4, AGO5, and RDR6 genes during GPGV infection, suggesting the activation of the posttranscriptional gene-silencing (PTGS) pathway as a plant antiviral defense. PTGS suppression assays in transgenic N. benthamiana 16c plants revealed the ability of the GPGV coat protein to suppress RNA silencing. This work provides novel insights on the interaction between GPGV and its host, revealing the ability of the virus to trigger and suppress antiviral RNA silencing.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Giulia Tarquini
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Udine I-33100, Italy
| | - Laura Pagliari
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Udine I-33100, Italy
| | - Paolo Ermacora
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Udine I-33100, Italy
| | - Rita Musetti
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Udine I-33100, Italy
| | - Giuseppe Firrao
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Udine I-33100, Italy
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Wang L, Chen W, Ma H, Li J, Hao X, Wu Y. Identification of RNA silencing suppressor encoded by wheat blue dwarf (WBD) phytoplasma. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:843-849. [PMID: 33749977 DOI: 10.1111/plb.13257] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/14/2021] [Indexed: 06/12/2023]
Abstract
Plants possess an innate immune system for defence against pathogens. In turn, pathogens have various strategies to overcome complex plant defences. Among diverse pathogens, phytoplasmas are associated with serious diseases in a range of species. RNA silencing serves as an efficient defence system against pathogens in eukaryotes but can be interrupted by RNA silencing suppressors (RSSs) encoded by pathogens. Currently, many RSSs have been identified in viruses, bacteria, oomycetes and fungi. Phytoplasmas are pathogens in several hundred plant species. In this research, 37 candidate effectors of wheat blue dwarf (WBD) phytoplasma were screened for presence of RSS. Agro-infiltration assay, yeast expression system, floral-dip method for constructing transgenic A. thaliana, Western blotting and RT-qPCR were used for identification of RNA silencing suppressors. SWP16 encoded by WBD phytoplasma was found to be a secretory protein that inhibited accumulation of GFP siRNA and led to the accumulation of GPF mRNA in systemic N. benthamiana 16c. Furthermore, in A. thaliana SWP16 inhibited production of miRNAs, which are components of RNA silencing. SWP16 also promoted infection of potato virus X. We conclude that SWP16 encoded by WBD phytoplasma was an RSS, suppressing systemic RNA silencing. This is the first evidence that a phytoplasma encodes an RSS and provides a theoretical basis for research on the interaction mechanisms between pathogens and plants.
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Affiliation(s)
- L Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest Agriculture & Forestry University, Yangling, P. R. China
| | - W Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest Agriculture & Forestry University, Yangling, P. R. China
| | - H Ma
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest Agriculture & Forestry University, Yangling, P. R. China
| | - J Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest Agriculture & Forestry University, Yangling, P. R. China
| | - X Hao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest Agriculture & Forestry University, Yangling, P. R. China
| | - Y Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest Agriculture & Forestry University, Yangling, P. R. China
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Sun D, Li Y, Ma Z, Yan X, Li N, Shang B, Hu X, Cui K, Koiwa H, Zhang X. The epigenetic factor FVE orchestrates cytoplasmic SGS3-DRB4-DCL4 activities to promote transgene silencing in Arabidopsis. SCIENCE ADVANCES 2021; 7:7/32/eabf3898. [PMID: 34348894 PMCID: PMC8336953 DOI: 10.1126/sciadv.abf3898] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 06/15/2021] [Indexed: 05/27/2023]
Abstract
Posttranscriptional gene silencing (PTGS) is a regulatory mechanism to suppress undesired transcripts. Here, we identified Flowering locus VE (FVE), a well-known epigenetic component, as a new player in cytoplasmic PTGS. Loss-of-function fve mutations substantially reduced the accumulation of transgene-derived small interfering RNAs (siRNAs). FVE interacts with suppressor of gene silencing 3 (SGS3), a master component in PTGS. FVE promotes SGS3 homodimerization that is essential for its function. FVE can bind to single-stranded RNA and double-stranded RNA (dsRNA) with moderate affinities, while its truncated form FVE-8 has a significantly increased binding affinity to dsRNA. These affinities affect the association and channeling of SGS3-RNA to downstream dsRNA binding protein 4 (DRB4)/Dicer-like protein 2/4 (DCL2/4) complexes. Hence, FVE, but not FVE-8, biochemically enhances the DRB4/DCL2/4 activity in vitro. We surmise that FVE promotes production of transgene-derived siRNAs through concertedly tuning SGS3-DRB4/DCL2/4 functions. Thus, this study revealed a noncanonical role of FVE in PTGS.
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Affiliation(s)
- Di Sun
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Yanjun Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Zeyang Ma
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Xingxing Yan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Niankui Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Baoshuan Shang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Xiaomei Hu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Kai Cui
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Research Institute of Resources Insects, Chinese Academy of Forestry, Kunming 650224, China
| | - Hisashi Koiwa
- Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Xiuren Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA.
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Ambrós S, Gómez-Muñoz N, Giménez-Santamarina S, Sánchez-Vicente J, Navarro-López J, Martínez F, Daròs JA, Rodrigo G. Molecular signatures of silencing suppression degeneracy from a complex RNA virus. PLoS Comput Biol 2021; 17:e1009166. [PMID: 34181647 PMCID: PMC8270454 DOI: 10.1371/journal.pcbi.1009166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 07/09/2021] [Accepted: 06/09/2021] [Indexed: 11/21/2022] Open
Abstract
As genomic architectures become more complex, they begin to accumulate degenerate and redundant elements. However, analyses of the molecular mechanisms underlying these genetic architecture features remain scarce, especially in compact but sufficiently complex genomes. In the present study, we followed a proteomic approach together with a computational network analysis to reveal molecular signatures of protein function degeneracy from a plant virus (as virus-host protein-protein interactions). We employed affinity purification coupled to mass spectrometry to detect several host factors interacting with two proteins of Citrus tristeza virus (p20 and p25) that are known to function as RNA silencing suppressors, using an experimental system of transient expression in a model plant. The study was expanded by considering two different isolates of the virus, and some key interactions were confirmed by bimolecular fluorescence complementation assays. We found that p20 and p25 target a common set of plant proteins including chloroplastic proteins and translation factors. Moreover, we noted that even specific targets of each viral protein overlap in function. Notably, we identified argonaute proteins (key players in RNA silencing) as reliable targets of p20. Furthermore, we found that these viral proteins preferentially do not target hubs in the host protein interactome, but elements that can transfer information by bridging different parts of the interactome. Overall, our results demonstrate that two distinct proteins encoded in the same viral genome that overlap in function also overlap in their interactions with the cell proteome, thereby highlighting an overlooked connection from a degenerate viral system.
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Affiliation(s)
- Silvia Ambrós
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Spain
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC–Universitat Politècnica de València, València, Spain
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC–Universitat de València, Paterna, Spain
| | - Neus Gómez-Muñoz
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Spain
| | - Silvia Giménez-Santamarina
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC–Universitat Politècnica de València, València, Spain
| | - Javier Sánchez-Vicente
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC–Universitat Politècnica de València, València, Spain
| | - Josep Navarro-López
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Spain
| | - Fernando Martínez
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC–Universitat Politècnica de València, València, Spain
| | - José-Antonio Daròs
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC–Universitat Politècnica de València, València, Spain
| | - Guillermo Rodrigo
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC–Universitat Politècnica de València, València, Spain
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC–Universitat de València, Paterna, Spain
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Decle-Carrasco S, Rodríguez-Zapata LC, Castano E. Plant viral proteins and fibrillarin: the link to complete the infective cycle. Mol Biol Rep 2021; 48:4677-4686. [PMID: 34036480 DOI: 10.1007/s11033-021-06401-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/08/2021] [Indexed: 10/21/2022]
Abstract
The interaction between viruses with the nucleolus is already a well-defined field of study in plant virology. This interaction is not restricted to those viruses that replicate in the nucleus, in fact, RNA viruses that replicate exclusively in the cytoplasm express proteins that localize in the nucleolus. Some positive single stranded RNA viruses from animals and plants have been reported to interact with the main nucleolar protein, Fibrillarin. Among nucleolar proteins, Fibrillarin is an essential protein that has been conserved in sequence and function throughout evolution. Fibrillarin is a methyltransferase protein with more than 100 methylation sites in the pre-ribosomal RNA, involved in multiple cellular processes, including initiation of transcription, oncogenesis, and apoptosis, among others. Recently, it was found that AtFib2 shows a ribonuclease activity. In plant viruses, Fibrillarin is involved in long-distance movement and cell-to-cell movement, being two highly different processes. The mechanism that Fibrillarin performs is still unknown. However, and despite belonging to very different viral families, the majority comply with the following. (1) They are positive single stranded RNA viruses; (2) encode different types of viral proteins that partially localize in the nucleolus; (3) interacts with Fibrillarin exporting it to the cytoplasm; (4) the viral protein-Fibrillarin interaction forms an RNP complex with the viral RNA and; (5) Fibrillarin depletion affects the infective cycle of the virus. Here we review the relationship of those plant viruses with Fibrillarin interaction, with special focus on the molecular processes of the virus to sequester Fibrillarin to complete its infective cycle.
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Affiliation(s)
- Stefano Decle-Carrasco
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Luis Carlos Rodríguez-Zapata
- Unidad de Biotecnología. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Enrique Castano
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México.
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50
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Decle-Carrasco S, Rodríguez-Zapata LC, Castano E. Plant viral proteins and fibrillarin: the link to complete the infective cycle. Mol Biol Rep 2021. [PMID: 34036480 DOI: 10.1007/s11033-021-06401-1/tables/1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
The interaction between viruses with the nucleolus is already a well-defined field of study in plant virology. This interaction is not restricted to those viruses that replicate in the nucleus, in fact, RNA viruses that replicate exclusively in the cytoplasm express proteins that localize in the nucleolus. Some positive single stranded RNA viruses from animals and plants have been reported to interact with the main nucleolar protein, Fibrillarin. Among nucleolar proteins, Fibrillarin is an essential protein that has been conserved in sequence and function throughout evolution. Fibrillarin is a methyltransferase protein with more than 100 methylation sites in the pre-ribosomal RNA, involved in multiple cellular processes, including initiation of transcription, oncogenesis, and apoptosis, among others. Recently, it was found that AtFib2 shows a ribonuclease activity. In plant viruses, Fibrillarin is involved in long-distance movement and cell-to-cell movement, being two highly different processes. The mechanism that Fibrillarin performs is still unknown. However, and despite belonging to very different viral families, the majority comply with the following. (1) They are positive single stranded RNA viruses; (2) encode different types of viral proteins that partially localize in the nucleolus; (3) interacts with Fibrillarin exporting it to the cytoplasm; (4) the viral protein-Fibrillarin interaction forms an RNP complex with the viral RNA and; (5) Fibrillarin depletion affects the infective cycle of the virus. Here we review the relationship of those plant viruses with Fibrillarin interaction, with special focus on the molecular processes of the virus to sequester Fibrillarin to complete its infective cycle.
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Affiliation(s)
- Stefano Decle-Carrasco
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Luis Carlos Rodríguez-Zapata
- Unidad de Biotecnología. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Enrique Castano
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México.
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