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Naresh M, Purkayastha A, Dasgupta I. P4 protein of an Indian isolate of rice tungro bacilliform virus modulates gene silencing. Virus Genes 2024; 60:55-64. [PMID: 38055154 DOI: 10.1007/s11262-023-02039-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 11/09/2023] [Indexed: 12/07/2023]
Abstract
Plant hosts and their viral pathogens are engaged in a constant cycle of defense and counter-defense as part of a molecular arms race, principal among them being the plant RNAi defense and the viral RNAi suppressor counter-defense. Rice tungro bacilliform virus (RTBV), member of the family Caulimoviridae, genus Tungrovirus, species Tungrovirus oryzae, infects rice in South- and Southeast Asia and causes severe symptoms of stunting, yellow-orange discoloration and twisting of leaf tips. To better understand the possible counter-defensive roles of RTBV against the host RNAi defense system, we explored the ability of the P4 protein of an Indian isolate of RTBV to act as a possible modulator of RNAi. Using a transient silencing and silencing suppression assay in Nicotiana benthamiana, we show that P4 not only displays an RNAi suppressor function, but also potentially enhances RNAi. The results also suggests that the N-terminal 168 amino acid residues of P4 are sufficient to maintain RNAi suppressor activity. Taken together with the earlier reports this work strengthens the view that the P4 protein carries out RNAi suppressor and a potential RNAi enhancer function.
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Affiliation(s)
- Madhvi Naresh
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India
| | - Arunima Purkayastha
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India
| | - Indranil Dasgupta
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India.
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2
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Shakir S, Mubin M, Nahid N, Serfraz S, Qureshi MA, Lee TK, Liaqat I, Lee S, Nawaz-ul-Rehman MS. REPercussions: how geminiviruses recruit host factors for replication. Front Microbiol 2023; 14:1224221. [PMID: 37799604 PMCID: PMC10548238 DOI: 10.3389/fmicb.2023.1224221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 08/21/2023] [Indexed: 10/07/2023] Open
Abstract
Circular single-stranded DNA viruses of the family Geminiviridae encode replication-associated protein (Rep), which is a multifunctional protein involved in virus DNA replication, transcription of virus genes, and suppression of host defense responses. Geminivirus genomes are replicated through the interaction between virus Rep and several host proteins. The Rep also interacts with itself and the virus replication enhancer protein (REn), which is another essential component of the geminivirus replicase complex that interacts with host DNA polymerases α and δ. Recent studies revealed the structural and functional complexities of geminivirus Rep, which is believed to have evolved from plasmids containing a signature domain (HUH) for single-stranded DNA binding with nuclease activity. The Rep coding sequence encompasses the entire coding sequence for AC4, which is intricately embedded within it, and performs several overlapping functions like Rep, supporting virus infection. This review investigated the structural and functional diversity of the geminivirus Rep.
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Affiliation(s)
- Sara Shakir
- Plant Genetics Lab, Gembloux Agro-Bio Tech, University of Liѐge, Gembloux, Belgium
| | - Muhammad Mubin
- Virology Lab, Center for Agricultural Biochemistry and Biotechnology, University of Agriculture, Faisalabad, Faisalabad, Pakistan
| | - Nazia Nahid
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
| | - Saad Serfraz
- Virology Lab, Center for Agricultural Biochemistry and Biotechnology, University of Agriculture, Faisalabad, Faisalabad, Pakistan
| | - Muhammad Amir Qureshi
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, Republic of Korea
| | - Taek-Kyun Lee
- Risk Assessment Research Center, Korea Institute of Ocean Science and Technology, Geoje, Republic of Korea
| | - Iram Liaqat
- Microbiology Lab, Department of Zoology, Government College University, Lahore, Pakistan
| | - Sukchan Lee
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, Republic of Korea
| | - Muhammad Shah Nawaz-ul-Rehman
- Virology Lab, Center for Agricultural Biochemistry and Biotechnology, University of Agriculture, Faisalabad, Faisalabad, Pakistan
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3
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Zhang J, Ma M, Liu Y, Ismayil A. Plant Defense and Viral Counter-Defense during Plant-Geminivirus Interactions. Viruses 2023; 15:v15020510. [PMID: 36851725 PMCID: PMC9964946 DOI: 10.3390/v15020510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/17/2023] Open
Abstract
Geminiviruses are the largest family of plant viruses that cause severe diseases and devastating yield losses of economically important crops worldwide. In response to geminivirus infection, plants have evolved ingenious defense mechanisms to diminish or eliminate invading viral pathogens. However, increasing evidence shows that geminiviruses can interfere with plant defense response and create a suitable cell environment by hijacking host plant machinery to achieve successful infections. In this review, we discuss recent findings about plant defense and viral counter-defense during plant-geminivirus interactions.
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Affiliation(s)
- Jianhang Zhang
- Key Laboratory of Xinjiang Phytomedicine Resource and Utilization of Ministry of Education, College of Life Sciences, Shihezi University, Shihezi 832003, China
| | - Mengyuan Ma
- Key Laboratory of Xinjiang Phytomedicine Resource and Utilization of Ministry of Education, College of Life Sciences, Shihezi University, Shihezi 832003, China
| | - Yule Liu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Asigul Ismayil
- Key Laboratory of Xinjiang Phytomedicine Resource and Utilization of Ministry of Education, College of Life Sciences, Shihezi University, Shihezi 832003, China
- Correspondence:
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Kumar R, Dasgupta I. Geminiviral C4/AC4 proteins: An emerging component of the viral arsenal against plant defence. Virology 2023; 579:156-168. [PMID: 36693289 DOI: 10.1016/j.virol.2023.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 12/26/2022] [Accepted: 01/08/2023] [Indexed: 01/12/2023]
Abstract
Virus infection triggers a plethora of defence reactions in plants to incapacitate the intruder. Viruses, in turn, have added additional functions to their genes so that they acquire capabilities to neutralize the above defence reactions. In plant-infecting viruses, the family Geminiviridae comprises members, majority of whom encode 6-8 genes in their small single-stranded DNA genomes. Of the above genes, one which shows the most variability in its amino acid sequence is the C4/AC4. Recent studies have uncovered evidence, which point towards a wide repertoire of functions performed by C4/AC4 revealing its role as a major player in suppressing plant defence. This review summarizes the various plant defence mechanisms against viruses and highlights how C4/AC4 has evolved to counter most of them.
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Affiliation(s)
- Rohit Kumar
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Indranil Dasgupta
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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5
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Arora H, Singh RK, Sharma S, Sharma N, Panchal A, Das T, Prasad A, Prasad M. DNA methylation dynamics in response to abiotic and pathogen stress in plants. Plant Cell Rep 2022; 41:1931-1944. [PMID: 35833989 DOI: 10.1007/s00299-022-02901-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
DNA methylation is a dynamic epigenetic mechanism that plays a significant role in gene expression and also maintains chromatin stability. The process is conserved in both plants and animals, and crucial for development and stress responses. Differential DNA methylation during adverse environmental conditions or pathogen attack facilitates the selective expression of defense-related genes. Both stress-induced DNA hypomethylation and hypermethylation play beneficial roles in activating the defense response. These DNA marks may be carried to the next generation making the progenies 'primed' for abiotic and biotic stress responses. Over the recent years, rapid advancements in the area of high throughput sequencing have enabled the detection of methylation status at genome levels in several plant species. Epigenotyping offers an alternative tool to plant breeders in addition to conventional markers for the selection of the desired offspring. In this review, we briefly discuss the mechanism of DNA methylation, recent understanding of DNA methylation-mediated gene regulation during abiotic and biotic stress responses, and stress memory in plants.
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Affiliation(s)
- Heena Arora
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Roshan Kumar Singh
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Shambhavi Sharma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Namisha Sharma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
- Institute of Life Sciences, NALCO Nagar, Bhubaneswar, 751023, India
| | - Anurag Panchal
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Tuhin Das
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Ashish Prasad
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Manoj Prasad
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India.
- Department of Plant Sciences, University of Hyderabad, Hyderabad, Telangana, 500046, India.
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Chowdhury S, Mukherjee A, Basak S, Das R, Mandal A, Kundu P. Disruption of tomato TGS machinery by ToLCNDV causes reprogramming of vascular tissue-specific TORNADO1 gene expression. Planta 2022; 256:78. [PMID: 36094622 DOI: 10.1007/s00425-022-03985-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
Vascular development-related TRN1 transcription is suppressed by cytosine methylation in fully developed leaves of tomato. ToLCNDV infection disrupts methylation machinery and reactivates TRN1 expression - likely causing abnormal leaf growth pattern. Leaf curl disease of tomato caused by tomato leaf curl New Delhi virus (ToLCNDV) inflicts huge economical loss. Disease symptoms resemble leaf developmental defects including abnormal vein architecture. Leaf vein patterning-related TORNADO1 gene's (SlTRN1) transcript level is augmented in virus-infected leaves. To elucidate the molecular mechanism of the upregulation of SlTRN1 in vivo, we have deployed SlTRN1 promoter-reporter transgenic tomato plants and investigated the gene's dynamic expression pattern in leaf growth stages and infection. Expression of the gene was delimited in the vascular tissues and suppressed in fully developed leaves. WRKY16 transcription factor readily activated SlTRN1 promoter in varied sized leaves and upon virus infection, while silencing of WRKY16 gene resulted in dampened promoter activity. Methylation-sensitive PCR analyses confirmed the accumulation of CHH methylation at multiple locations in the SlTRN1 promoter in older leaves. However, ToLCNDV infection reverses the methylation status and restores expression level in the leaf vascular bundle. The virus dampens the level of key maintenance and de novo DNA methyltransferases SlDRM5, SlMET1, SlCMT2 with concomitant augmentation of two DNA demethylases, SlDML1 and SlDML2 levels in SlTRN1 promoter-reporter transgenics. Transient overexpression of SlDML2 mimics the virus-induced hypomethylation state of the SlTRN1 promoter in mature leaves, while silencing of SlDML2 lessens promoter activity. Furthermore, in line with the previous studies, we confirm the crucial role of viral suppressors of RNA silencing AC2 and AC4 proteins in promoting DNA demethylation and directing it to restore activated transcription of SlTRN1. Unusually elevated expression of SlTRN1 may negatively impact normal growth of leaves.
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Affiliation(s)
- Shreya Chowdhury
- Division of Plant Biology, Bose Institute, EN Block, Sector V, Bidhan Nagar, Kolkata, 700091, West Bengal, India
| | - Ananya Mukherjee
- Division of Plant Biology, Bose Institute, EN Block, Sector V, Bidhan Nagar, Kolkata, 700091, West Bengal, India
| | - Shrabani Basak
- Division of Plant Biology, Bose Institute, EN Block, Sector V, Bidhan Nagar, Kolkata, 700091, West Bengal, India
| | - Rohit Das
- Division of Plant Biology, Bose Institute, EN Block, Sector V, Bidhan Nagar, Kolkata, 700091, West Bengal, India
| | - Arunava Mandal
- Division of Plant Biology, Bose Institute, EN Block, Sector V, Bidhan Nagar, Kolkata, 700091, West Bengal, India
- Department of Genetics, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India
| | - Pallob Kundu
- Division of Plant Biology, Bose Institute, EN Block, Sector V, Bidhan Nagar, Kolkata, 700091, West Bengal, India.
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7
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Zhao L, Che X, Wang Z, Zhou X, Xie Y. Functional Characterization of Replication-Associated Proteins Encoded by Alphasatellites Identified in Yunnan Province, China. Viruses 2022; 14:222. [PMID: 35215816 PMCID: PMC8875141 DOI: 10.3390/v14020222] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/17/2022] [Accepted: 01/21/2022] [Indexed: 12/20/2022] Open
Abstract
Alphasatellites, which encode only a replication-associated protein (alpha-Rep), are frequently found to be non-essential satellite components associated with begomovirus/betasatellite complexes, and their presence can modulate disease symptoms and/or viral DNA accumulation during infection. Our previous study has shown that there are three types of alphasatellites associated with begomovirus/betasatellite complexes in Yunnan province in China and they encode three corresponding types of alpha-Rep proteins. However, the biological functions of alpha-Reps remain poorly understood. In this study, we investigated the biological functions of alpha-Reps in post-transcriptional gene silencing (PTGS) and transcriptional gene silencing (TGS) using 16c and 16-TGS transgenic Nicotiana benthamiana plants. Results showed that all the three types of alpha-Rep proteins were capable of suppressing the PTGS and reversing the TGS. Among them, the alpha-Rep of Y10DNA1 has the strongest PTGS and TGS suppressor activities. We also found that the alpha-Rep proteins were able to increase the accumulation of their helper virus during coinfection. These results suggest that the alpha-Reps may have a role in overcoming host defense, which provides a possible explanation for the selective advantage provided by the association of alphasatellites with begomovirus/betasatellite complexes.
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Affiliation(s)
- Liling Zhao
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (L.Z.); (X.C.); (X.Z.)
- Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650223, China
| | - Xuan Che
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (L.Z.); (X.C.); (X.Z.)
| | - Zhanqi Wang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Sciences, Huzhou University, Huzhou 313000, China;
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (L.Z.); (X.C.); (X.Z.)
- Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yan Xie
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (L.Z.); (X.C.); (X.Z.)
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8
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Ghosh D, M M, Chakraborty S. Impact of viral silencing suppressors on plant viral synergism: a global agro-economic concern. Appl Microbiol Biotechnol 2021; 105:6301-6313. [PMID: 34423406 DOI: 10.1007/s00253-021-11483-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 12/27/2022]
Abstract
Plant viruses are known for their devastating impact on global agriculture. These intracellular biotrophic pathogens can infect a wide variety of plant hosts all over the world. The synergistic association of plant viruses makes the situation more alarming. It usually promotes the replication, movement, and transmission of either or both the coexisting synergistic viral partners. Although plants elicit a robust antiviral immune reaction, including gene silencing, to limit these infamous invaders, viruses counter it by encoding viral suppressors of RNA silencing (VSRs). Growing evidence also suggests that VSRs play a driving role in mediating the plant viral synergism. This review briefly discusses the evil impacts of mixed infections, especially synergism, and then comprehensively describes the emerging roles of VSRs in mediating the synergistic association of plant viruses. KEY POINTS: • Synergistic associations of plant viruses have devastating impacts on global agriculture. • Viral suppressors of RNA silencing (VSRs) play key roles in driving plant viral synergism.
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Affiliation(s)
- Dibyendu Ghosh
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Malavika M
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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Teixeira RM, Ferreira MA, Raimundo GAS, Fontes EPB. Geminiviral Triggers and Suppressors of Plant Antiviral Immunity. Microorganisms 2021; 9:microorganisms9040775. [PMID: 33917649 PMCID: PMC8067988 DOI: 10.3390/microorganisms9040775] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 03/26/2021] [Accepted: 03/26/2021] [Indexed: 12/19/2022] Open
Abstract
Geminiviruses are circular single-stranded DNA plant viruses encapsidated into geminate virion particles, which infect many crops and vegetables and, hence, represent significant agricultural constraints worldwide. To maintain their broad-range host spectrum and establish productive infection, the geminiviruses must circumvent a potent plant antiviral immune system, which consists of a multilayered perception system represented by RNA interference sensors and effectors, pattern recognition receptors (PRR), and resistance (R) proteins. This recognition system leads to the activation of conserved defense responses that protect plants against different co-existing viral and nonviral pathogens in nature. Furthermore, a specific antiviral cell surface receptor signaling is activated at the onset of geminivirus infection to suppress global translation. This review highlighted these layers of virus perception and host defenses and the mechanisms developed by geminiviruses to overcome the plant antiviral immunity mechanisms.
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Deom CM, Alabady MS, Yang L. Early transcriptome changes induced by the Geminivirus C4 oncoprotein: setting the stage for oncogenesis. BMC Genomics 2021; 22:147. [PMID: 33653270 PMCID: PMC7923490 DOI: 10.1186/s12864-021-07455-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 02/19/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The Beet curly top virus C4 oncoprotein is a pathogenic determinant capable of inducing extensive developmental abnormalities. No studies to date have investigated how the transcriptional profiles differ between plants expressing or not expressing the C4 oncoprotein. RESULTS We investigated early transcriptional changes in Arabidopsis associated with expression of the Beet curly top virus C4 protein that represent initial events in pathogenesis via a comparative transcriptional analysis of mRNAs and small RNAs. We identified 48 and 94 differentially expressed genes at 6- and 12-h post-induction versus control plants. These early time points were selected to focus on direct regulatory effects of C4 expression. Since previous evidence suggested that the C4 protein regulated the brassinosteroid (BR)-signaling pathway, differentially expressed genes could be divided into two groups: those responsive to alterations in the BR-signaling pathway and those uniquely responsive to C4. Early transcriptional changes that disrupted hormone homeostasis, 18 and 19 differentially expressed genes at both 6- and 12-hpi, respectively, were responsive to C4-induced regulation of the BR-signaling pathway. Other C4-induced differentially expressed genes appeared independent of the BR-signaling pathway at 12-hpi, including changes that could alter cell development (4 genes), cell wall homeostasis (5 genes), redox homeostasis (11 genes) and lipid transport (4 genes). Minimal effects were observed on expression of small RNAs. CONCLUSION This work identifies initial events in genetic regulation induced by a geminivirus C4 oncoprotein. We provide evidence suggesting the C4 protein regulates multiple regulatory pathways and provides valuable insights into the role of the C4 protein in regulating initial events in pathogenesis.
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Affiliation(s)
- Carl Michael Deom
- Department of Plant Pathology, University of Georgia, Athens, GA, USA.
| | - Magdy S Alabady
- Department of Plant Biology, University of Georgia, Athens, GA, USA
| | - Li Yang
- Department of Plant Pathology, University of Georgia, Athens, GA, USA
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11
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Sáez C, Flores-León A, Montero-Pau J, Sifres A, Dhillon NPS, López C, Picó B. RNA-Seq Transcriptome Analysis Provides Candidate Genes for Resistance to Tomato Leaf Curl New Delhi Virus in Melon. Front Plant Sci 2021; 12:798858. [PMID: 35116050 PMCID: PMC8805612 DOI: 10.3389/fpls.2021.798858] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 11/29/2021] [Indexed: 05/10/2023]
Abstract
Tomato leaf curl New Delhi virus (ToLCNDV) emerged in the Mediterranean Basin in 2012 as the first DNA bipartite begomovirus (Geminiviridae family), causing severe yield and economic losses in cucurbit crops. A major resistance locus was identified in the wild melon accession WM-7 (Cucumis melo kachri group), but the mechanisms involved in the resistant response remained unknown. In this work, we used RNA-sequencing to identify disease-associated genes that are differentially expressed in the course of ToLCNDV infection and could contribute to resistance. Transcriptomes of the resistant WM-7 genotype and the susceptible cultivar Piñonet Piel de Sapo (PS) (C. melo ibericus group) in ToLCNDV and mock inoculated plants were compared at four time points during infection (0, 3, 6, and 12 days post inoculation). Different gene expression patterns were observed over time in the resistant and susceptible genotypes in comparison to their respective controls. Differentially expressed genes (DEGs) in ToLCNDV-infected plants were classified using gene ontology (GO) terms, and genes of the categories transcription, DNA replication, and helicase activity were downregulated in WM-7 but upregulated in PS, suggesting that reduced activity of these functions reduces ToLCNDV replication and intercellular spread and thereby contributes to resistance. DEGs involved in the jasmonic acid signaling pathway, photosynthesis, RNA silencing, transmembrane, and sugar transporters entail adverse consequences for systemic infection in the resistant genotype, and lead to susceptibility in PS. The expression levels of selected candidate genes were validated by qRT-PCR to corroborate their differential expression upon ToLCNDV infection in resistant and susceptible melon. Furthermore, single nucleotide polymorphism (SNPs) with an effect on structural functionality of DEGs linked to the main QTLs for ToLCNDV resistance have been identified. The obtained results pinpoint cellular functions and candidate genes that are differentially expressed in a resistant and susceptible melon line in response to ToLCNDV, an information of great relevance for breeding ToLCNDV-resistant melon cultivars.
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Affiliation(s)
- Cristina Sáez
- Institute for the Conservation and Breeding of Agricultural Biodiversity, Universitat Politècnica de València, Valencia, Spain
- *Correspondence: Cristina Sáez,
| | - Alejandro Flores-León
- Institute for the Conservation and Breeding of Agricultural Biodiversity, Universitat Politècnica de València, Valencia, Spain
| | - Javier Montero-Pau
- Cavanilles Institute of Biodiversity and Evolutionary Biology, Universitat de València, Valencia, Spain
| | - Alicia Sifres
- Institute for the Conservation and Breeding of Agricultural Biodiversity, Universitat Politècnica de València, Valencia, Spain
| | - Narinder P. S. Dhillon
- World Vegetable Center, East and Southeast Asia, Research and Training Station, Kasetsart University, Nakhon Pathom, Thailand
| | - Carmelo López
- Institute for the Conservation and Breeding of Agricultural Biodiversity, Universitat Politècnica de València, Valencia, Spain
- Carmelo López,
| | - Belén Picó
- Institute for the Conservation and Breeding of Agricultural Biodiversity, Universitat Politècnica de València, Valencia, Spain
- Belén Picó,
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12
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Zarreen F, Chakraborty S. Epigenetic regulation of geminivirus pathogenesis: a case of relentless recalibration of defence responses in plants. J Exp Bot 2020; 71:6890-6906. [PMID: 32869846 DOI: 10.1093/jxb/eraa406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 08/27/2020] [Indexed: 06/11/2023]
Abstract
Geminiviruses constitute one of the largest families of plant viruses and they infect many economically important crops. The proteins encoded by the single-stranded DNA genome of these viruses interact with a wide range of host proteins to cause global dysregulation of cellular processes and help establish infection in the host. Geminiviruses have evolved numerous mechanisms to exploit host epigenetic processes to ensure the replication and survival of the viral genome. Here, we review our current knowledge of diverse epigenetic processes that have been implicated in the regulation of geminivirus pathogenesis, including DNA methylation, histone post-transcriptional modification, chromatin remodelling, and nucleosome repositioning. In addition, we discuss the currently limited evidence of host epigenetic defence responses that are aimed at counteracting geminivirus infection, and the potential for exploiting these responses for the generation of resistance against geminiviruses in crop species.
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Affiliation(s)
- Fauzia Zarreen
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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13
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Silva-Martins G, Bolaji A, Moffett P. What does it take to be antiviral? An Argonaute-centered perspective on plant antiviral defense. J Exp Bot 2020; 71:6197-6210. [PMID: 32835379 DOI: 10.1093/jxb/eraa377] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 08/12/2020] [Indexed: 06/11/2023]
Abstract
RNA silencing is a major mechanism of constitutive antiviral defense in plants, mediated by a number of proteins, including the Dicer-like (DCL) and Argonaute (AGO) endoribonucleases. Both DCL and AGO protein families comprise multiple members. In particular, the AGO protein family has expanded considerably in different plant lineages, with different family members having specialized functions. Although the general mode of action of AGO proteins is well established, the properties that make different AGO proteins more or less efficient at targeting viruses are less well understood. In this report, we review methodologies used to study AGO antiviral activity and current knowledge about which AGO family members are involved in antiviral defense. In addition, we discuss what is known about the different properties of AGO proteins thought to be associated with this function.
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Affiliation(s)
| | - Ayooluwa Bolaji
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Peter Moffett
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
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Ogden AJ, Boukari W, Nava A, Lucinda N, Sunter G, Curtis WR, Adkins JN, Polston JE. Characterization of Local and Systemic Impact of Whitefly ( Bemisia tabaci) Feeding and Whitefly-Transmitted Tomato Mottle Virus Infection on Tomato Leaves by Comprehensive Proteomics. Int J Mol Sci 2020; 21:E7241. [PMID: 33008056 DOI: 10.3390/ijms21197241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/21/2020] [Accepted: 09/26/2020] [Indexed: 11/23/2022] Open
Abstract
Tomato mottle virus (ToMoV) is a single-stranded DNA (ssDNA) begomovirus transmitted to solanaceous crops by the whitefly species complex (Bemisia tabaci), causing stunted growth, leaf mottling, and reduced yield. Using a genetic repertoire of seven genes, ToMoV pathogenesis includes the manipulation of multiple plant biological processes to circumvent antiviral defenses. To further understand the effects of whitefly feeding and whitefly-transmitted ToMoV infection on tomato plants (Solanum lycopersicum ‘Florida Lanai’), we generated comprehensive protein profiles of leaves subjected to feeding by either viruliferous whiteflies harboring ToMoV, or non-viruliferous whiteflies, or a no-feeding control. The effects of whitefly feeding and ToMoV infection were measured both locally and systemically by sampling either a mature leaf directly from the site of clip-cage confined whitefly feeding, or from a newly formed leaf 10 days post feeding (dpf). At 3 dpf, tomato’s response to ToMoV included proteins associated with translation initiation and elongation as well as plasmodesmata dynamics. In contrast, systemic impacts of ToMoV on younger leaves 10 dpf were more pronounced and included a virus-specific change in plant proteins associated with mRNA maturation and export, RNA-dependent DNA methylation, and other antiviral plant processes. Our analysis supports previous findings and provides novel insight into tomato’s local and systemic response to whitefly feeding and ToMoV infection.
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Vinutha T, Vanchinathan S, Bansal N, Kumar G, Permar V, Watts A, Ramesh SV, Praveen S. Tomato auxin biosynthesis/signaling is reprogrammed by the geminivirus to enhance its pathogenicity. Planta 2020; 252:51. [PMID: 32940767 DOI: 10.1007/s00425-020-03452-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/27/2020] [Indexed: 05/25/2023]
Abstract
Tomato leaf curl New Delhi virus-derived AC4 protein interacts with host proteins involved in auxin biosynthesis and reprograms auxin biosynthesis/signaling to help in viral replication and manifestation of the disease-associated symptoms. Perturbations of phytohormone-mediated gene regulatory network cause growth and developmental defects. Furthermore, plant viral infections cause characteristic disease symptoms similar to hormone-deficient mutants. Tomato leaf curl New Delhi Virus (ToLCNDV)-encoded AC4 is a small protein that attenuates the host transcriptional gene silencing, and aggravated disease severity in tomato is correlated with transcript abundance of AC4. Hence, investigating the role of AC4 in pathogenesis divulged that ToLCNDV-AC4 interacted with host TAR1 (tryptophan amino transferase 1)-like protein, CYP450 monooxygenase-the key enzyme of indole acetic acid (IAA) biosynthesis pathway-and with a protein encoded by senescence-associated gene involved in jasmonic acid pathway. Also, ToLCNDV infection resulted in the upregulation of host miRNAs, viz., miR164, miR167, miR393 and miR319 involved in auxin signaling and leaf morphogenesis concomitant with the decline in endogenous IAA levels. Ectopic overexpression of ToLCNDV-derived AC4 in tomato recapitulated the transcriptomic and disruption of auxin biosynthesis/signaling features of the infected leaves. Furthermore, exogenous foliar application of IAA caused remission of the characteristic disease-related symptoms in tomato. The roles of ToLCNDV-AC4 in reprogramming auxin biosynthesis, signaling and cross-talk with JA pathway to help viral replication and manifest the disease-associated symptoms during ToLCNDV infection are discussed.
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Affiliation(s)
- T Vinutha
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - S Vanchinathan
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Navita Bansal
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Gaurav Kumar
- Division of Biochemistry, ICAR-National Rice Research Institute, Cuttack, Orissa, 753006, India
| | - Vipin Permar
- Division of Plant Pathology-Advanced Centre for Plant Virology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Archana Watts
- Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - S V Ramesh
- ICAR-Division of Physiology, Biochemistry and PHT, ICAR-Central Plantation Crops Research Institute, Kasaragod, Kerala, 671124, India.
| | - Shelly Praveen
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
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Abstract
A continuing challenge to crop production worldwide is the spectrum of diseases caused by geminiviruses, a large family of small circular single-stranded DNA viruses. These viruses are quite diverse, some containing mono- or bi-partite genomes, and infecting a multitude of monocot and dicot plants. There are currently many efforts directed at controlling these diseases. While some of the methods include controlling the insect vector using pesticides or genetic insect resistance (Rodríguez-López et al., 2011), this review will focus on the generation of plants that are resistant to geminiviruses themselves. Genetic resistance was traditionally found by surveying the wild relatives of modern crops for resistance loci; this method is still widely used and successful. However, the quick rate of virus evolution demands a rapid turnover of resistance genes. With better information about virus-host interactions, scientists are now able to target early stages of geminivirus infection in the host, preventing symptom development and viral DNA accumulation.
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17
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Rodríguez-Gandarilla MG, Rodríguez-Negrete EA, Rivera-Bustamante RF. Superinfection by PHYVV Alters the Recovery Process in PepGMV-Infected Pepper Plants. Viruses 2020; 12:E286. [PMID: 32151060 DOI: 10.3390/v12030286] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/20/2020] [Accepted: 02/25/2020] [Indexed: 01/02/2023] Open
Abstract
Geminiviruses are important plant pathogens that affect crops around the world. In some geminivirus-host interactions, infected plants show recovery, a phenomenon characterized by symptom disappearance in newly emerging leaves. In pepper-Pepper golden mosaic virus (PepGMV) interaction, the host recovery process involves a silencing mechanism that includes both post-transcriptional (PTGS) and transcriptional (TGS) gene silencing pathways. Under field conditions, PepGMV is frequently found in mixed infections with Pepper huasteco yellow vein virus (PHYVV), another bipartite begomovirus. Mixed infected plants generally show a synergetic phenomenon and do not present recovery. Little is known about the molecular mechanism of this interaction. In the present study, we explored the effect of superinfection by PHYVV on a PepGMV-infected pepper plant showing recovery. Superinfection with PHYVV led to (a) the appearance of severe symptoms, (b) an increase of the levels of PepGMV DNA accumulation, (c) a decrease of the relative methylation levels of PepGMV DNA, and (d) an increase of chromatin activation marks present in viral minichromosomes. Finally, using heterologous expression and silencing suppression reporter systems, we found that PHYVV REn presents TGS silencing suppressor activity, whereas similar experiments suggest that Rep might be involved in suppressing PTGS.
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Loriato VAP, Martins LGC, Euclydes NC, Reis PAB, Duarte CEM, Fontes EPB. Engineering resistance against geminiviruses: A review of suppressed natural defenses and the use of RNAi and the CRISPR/Cas system. Plant Sci 2020; 292:110410. [PMID: 32005374 DOI: 10.1016/j.plantsci.2020.110410] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 11/22/2019] [Accepted: 01/07/2020] [Indexed: 05/21/2023]
Abstract
The Geminiviridae family is one of the most successful and largest families of plant viruses that infect a large variety of important dicotyledonous and monocotyledonous crops and cause significant yield losses worldwide. This broad spectrum of host range is only possible because geminiviruses have evolved sophisticated strategies to overcome the arsenal of antiviral defenses in such diverse plant species. In addition, geminiviruses evolve rapidly through recombination and pseudo-recombination to naturally create a great diversity of virus species with divergent genome sequences giving the virus an advantage over the host recognition system. Therefore, it is not surprising that efficient molecular strategies to combat geminivirus infection under open field conditions have not been fully addressed. In this review, we present the anti-geminiviral arsenal of plant defenses, the evolved virulence strategies of geminiviruses to overcome these plant defenses and the most recent strategies that have been engineered for transgenic resistance. Although, the in vitro reactivation of suppressed natural defenses as well as the use of RNAi and CRISPR/Cas systems hold the potential for achieving broad-range resistance and/or immunity, potential drawbacks have been associated with each case.
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Affiliation(s)
- Virgílio A P Loriato
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil; Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Laura G C Martins
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Nívea C Euclydes
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Pedro A B Reis
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil; Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Christiane E M Duarte
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil; Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Elizabeth P B Fontes
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil; Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
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Tzean Y, Chang HH, Tu TC, Hou BH, Chen HM, Chiu YS, Chou WY, Chang L, Yeh HH. Engineering Plant Resistance to Tomato Yellow Leaf Curl Thailand Virus Using a Phloem-Specific Promoter Expressing Hairpin RNA. Mol Plant Microbe Interact 2020; 33:87-97. [PMID: 31638467 DOI: 10.1094/mpmi-06-19-0158-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Transgenic approaches employing RNA interference (RNAi) strategies have been successfully applied to generate desired traits in plants; however, variations between RNAi transgenic siblings and the ability to quickly apply RNAi resistance to diverse cultivars remain challenging. In this study, we assessed the promoter activity of a cauliflower mosaic virus 35S promoter (35S) and a phloem-specific promoter derived from rice tungro bacilliform virus (RTBV) and their efficacy to drive RNAi against the endogenous glutamate-1-semialdehyde aminotransferase gene (GSA) that acts as a RNAi marker, through chlorophyll synthesis inhibition, and against tomato yellow leaf curl Thailand virus (TYLCTHV), a begomovirus (family Geminiviridae) reported to be the prevalent cause of tomato yellow leaf curl disease (TYLCD) in Taiwan. Transgenic Nicotiana benthamiana expressing hairpin RNA of GSA driven by either the 35S or RTBV promoter revealed that RTBV::hpGSA induced stronger silencing along the vein and more uniformed silencing phenotype among its siblings than 35S::hpGSA. Analysis of transgenic N. benthamiana, 35S::hpTYLCTHV, and RTBV::hpTYLCTHV revealed that, although 35S::hpTYLCTHV generated a higher abundance of small RNA than RTBV::hpTYLCTHV, RTBV::hpTYLCTHV transgenic plants conferred better TYLCTHV resistance than 35S::hpTYLCTHV. Grafting of wild-type (WT) scions to TYLCTHV RNAi rootstocks allowed transferable TYLCTHV resistance to the scion. A TYLCTHV-inoculation assay showed that noninfected WT scions were only observed when grafted to RTBV::hpTYLCTHV rootstocks but not 35S::hpTYLCTHV nor WT rootstocks. Together, our findings demonstrate an approach that may be widely applied to efficiently confer TYLCD resistance.
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Affiliation(s)
- Yuh Tzean
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Ho-Hsiung Chang
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Tsui-Chin Tu
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Bo-Han Hou
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Ho-Ming Chen
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Yi-Shu Chiu
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Wei-Yi Chou
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Li Chang
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Hsin-Hung Yeh
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
- Department of Plant Pathology and Microbiology, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Da'an District, Taipei 10617, Taiwan
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Walsh HA, Vanderschuren H, Taylor S, Rey MEC. RNA silencing of South African cassava mosaic virus in transgenic cassava expressing AC1/AC4 hp- RNA induces tolerance. ACTA ACUST UNITED AC 2019; 24:e00383. [PMID: 31763196 PMCID: PMC6864324 DOI: 10.1016/j.btre.2019.e00383] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/13/2019] [Accepted: 10/02/2019] [Indexed: 11/29/2022]
Abstract
A hairpin-RNA construct targeting South African cassava mosaic virus AC1/AC4 overlapping genome region confers tolerance in cassava. Viral load and symptom severity were significantly lower in transgenic lines transformed with AC1/AC4 construct compared to wildtype cv.60444. SACMV transgenic lines infected with SACMV displayed a recovery phenotype similar to cassava mosaic disease-tolerant cassava landrace TME3.
Cassava mosaic disease (CMD), caused by geminiviruses, is a major hurdle to cassava production. Due to the heterozygous nature of cassava, breeding for virus resistance is difficult, but cassava has been shown to be a good candidate for genetic engineering using RNA interference (RNAi). T This study reports on the ability of a transgene-derived RNA hairpin, homologous to an overlapping region of the SACMV replication associated protein and putative virus suppressor of silencing protein (AC1/AC4), to confer tolerance in the CMD-susceptible model cassava cultivar 60444. Three of the fourteen transgenic lines expressing SACMV AC1/AC4 hairpin-derived siRNAs showed decreased symptoms and viral loads compared to untransformed control plants. Expression of SACMV AC1/AC4 homologous siRNAs showed that this tolerance is most likely associated with post-transcriptional gene silencing of the virus. This is the first report of targeting the overlapping AC1 and AC4 genes of SACMV conferring CMD tolerance in cassava.
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Affiliation(s)
- H A Walsh
- School of Molecular and Cell Biology, University of the Witwatersrand, 1 Jan Smuts Ave, Johannesburg, South Africa
| | - H Vanderschuren
- Plant Genetics Laboratory, TERRA Teaching and Research Unit, University of Liège, Gembloux Agro-Bio Tech, Belgium
| | - S Taylor
- School of Molecular and Cell Biology, University of the Witwatersrand, 1 Jan Smuts Ave, Johannesburg, South Africa
| | - M E C Rey
- School of Molecular and Cell Biology, University of the Witwatersrand, 1 Jan Smuts Ave, Johannesburg, South Africa
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Li F, Wang A. RNA-Targeted Antiviral Immunity: More Than Just RNA Silencing. Trends Microbiol 2019; 27:792-805. [PMID: 31213342 DOI: 10.1016/j.tim.2019.05.007] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/08/2019] [Accepted: 05/15/2019] [Indexed: 11/21/2022]
Abstract
RNA silencing is a fundamental, evolutionarily conserved mechanism that regulates gene expression in eukaryotes. It also functions as a primary immune defense in microbes, such as viruses in plants. In addition to RNA silencing, RNA decay and RNA quality-control pathways are also two ancestral forms of intrinsic antiviral immunity, and the three RNA-targeted pathways may operate cooperatively for their antiviral function. Plant viruses encode viral suppressors of RNA silencing (VSRs) to suppress RNA silencing and facilitate virus infection. In response, plants may activate a counter-counter-defense mechanism to cope with VSR-mediated RNA silencing suppression. In this review, we summarize current knowledge of RNA silencing, RNA decay, and RNA quality control in antiviral defense, and highlight the mechanisms by which viruses compromise RNA-targeted immunity for their infection and survival in plants.
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