1
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Liu S, Ding SW. Antiviral RNA interference inhibits virus vertical transmission in plants. Cell Host Microbe 2024:S1931-3128(24)00316-0. [PMID: 39243759 DOI: 10.1016/j.chom.2024.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 07/14/2024] [Accepted: 08/12/2024] [Indexed: 09/09/2024]
Abstract
Known for over a century, seed transmission of plant viruses promotes trans-continental virus dissemination and provides the source of infection to trigger devastating disease epidemics in crops. However, it remains unknown whether there is a genetically defined immune pathway to suppress virus vertical transmission in plants. Here, we demonstrate potent immunosuppression of cucumber mosaic virus (CMV) seed transmission in its natural host Arabidopsis thaliana by antiviral RNA interference (RNAi) pathway. Immunofluorescence microscopy reveals predominant embryo infection at four stages of embryo development. We show that antiviral RNAi confers resistance to seed infection with different genetic requirements and drastically enhanced potency compared with the inhibition of systemic infection of whole plants. Moreover, we detect efficient seed transmission of a mutant CMV lacking its RNAi suppressor gene in mutant plants defective in antiviral RNAi, providing further support for the immunosuppression of seed transmission by antiviral RNAi.
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Affiliation(s)
- Si Liu
- Department of Microbiology & Plant Pathology and Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA
| | - Shou-Wei Ding
- Department of Microbiology & Plant Pathology and Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA.
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2
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He Z, Sheng S, Wang L, Dong T, Zhang K, Li L. Cucumber mosaic virus-induced gene and microRNA silencing in water dropwort (Oenanthe javanica (Blume) DC). PLANT METHODS 2024; 20:6. [PMID: 38212839 PMCID: PMC10782793 DOI: 10.1186/s13007-023-01129-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/20/2023] [Indexed: 01/13/2024]
Abstract
Water dropwort (Oenanthe javanica (Blume) DC), an aquatic perennial plant from the Apiaceae family, rich in dietary fibert, vitamins, and minerals. It usually grows in wet soils and water. Despite accumulating the transcriptomic data, gene function research on water dropwort is still far behind than that of the other crops. The cucumber mosaic virus (CMV) induced gene silencing was established to study the functions of gene and microRNA (miRNA) in the water dropwort. CMV Fast New York strain (CMV-Fny) genomic RNAs 1, 2, and 3 were individually cloned into pCB301 vectors. We deleted part of the ORF 2b region and introduced recognition sites. A CMV-induced gene silencing vector was employed to suppress the expression of endogenous genes, including phytoene desaturase (PDS). In order to assess the efficacy of gene silencing, we also cloned conserved sequence of gibberellin insensitive dwarf (GID1) cDNA sequences into the vector and inoculated the water dropwort. The height of CMV-GID1-infected plants was marginally reduced as a result of GID1 gene silencing, and their leaves were noticeably longer and thinner. Additionally, we also used a CMV-induced silencing vector to analyze the roles of endogenous miRNAs. We used a short tandem target mimic approach to clone miR319 and miR396 from water dropwort into the CMV vector. Plants with CMV-miRNA infection were driven to exhibit the distinctive phenotypes. We anticipate that functional genomic research on water dropwort will be facilitated by the CMV-induced gene silencing technique.
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Affiliation(s)
- Zhen He
- College of Plant Protection, Yangzhou University, Wenhui East Road No.48, Yangzhou, Jiangsu Province, 225009, People's Republic of China
| | - Shuangyu Sheng
- College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, People's Republic of China
| | - Lingqi Wang
- College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, People's Republic of China
| | - Tingting Dong
- College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, People's Republic of China
| | - Kun Zhang
- College of Plant Protection, Yangzhou University, Wenhui East Road No.48, Yangzhou, Jiangsu Province, 225009, People's Republic of China.
| | - Liangjun Li
- College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, People's Republic of China.
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3
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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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4
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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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5
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Guo H, Zhang Y, Li B, Li C, Shi Q, Zhu-Salzman K, Ge F, Sun Y. Salivary carbonic anhydrase II in winged aphid morph facilitates plant infection by viruses. Proc Natl Acad Sci U S A 2023; 120:e2222040120. [PMID: 36976769 PMCID: PMC10083582 DOI: 10.1073/pnas.2222040120] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 02/17/2023] [Indexed: 03/29/2023] Open
Abstract
Aphids are the most common insect vector transmitting hundreds of plant viruses. Aphid wing dimorphism (winged vs. wingless) not only showcases the phenotypic plasticity but also impacts virus transmission; however, the superiority of winged aphids in virus transmission over the wingless morph is not well understood. Here, we show that plant viruses were efficiently transmitted and highly infectious when associated with the winged morph of Myzus persicae and that a salivary protein contributed to this difference. The carbonic anhydrase II (CA-II) gene was identified by RNA-seq of salivary glands to have higher expression in the winged morph. Aphids secreted CA-II into the apoplastic region of plant cells, leading to elevated accumulation of H+. Apoplastic acidification further increased the activities of polygalacturonases, the cell wall homogalacturonan (HG)-modifying enzymes, promoting degradation of demethylesterified HGs. In response to apoplastic acidification, plants accelerated vesicle trafficking to enhance pectin transport and strengthen the cell wall, which also facilitated virus translocation from the endomembrane system to the apoplast. Secretion of a higher quantity of salivary CA-II by winged aphids promoted intercellular vesicle transport in the plant. The higher vesicle trafficking induced by winged aphids enhanced dispersal of virus particles from infected cells to neighboring cells, thus resulting in higher virus infection in plants relative to the wingless morph. These findings imply that the difference in the expression of salivary CA-II between winged and wingless morphs is correlated with the vector role of aphids during the posttransmission infection process, which influences the outcome of plant endurance of virus infection.
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Affiliation(s)
- Huijuan Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing100049, China
| | - Yanjing Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing100049, China
| | - Bingyu Li
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing100101, China
| | - Chenwei Li
- School of Life Sciences, Hebei University, Baoding071002, China
| | - Qingyun Shi
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing100049, China
| | - Keyan Zhu-Salzman
- Department of Entomology, Texas A&M University, College Station, TX77843
| | - Feng Ge
- Institute of Plant Protection, Shandong Academy of Agriculture Sciences, Jinan250100, China
| | - Yucheng Sun
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing100049, China
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6
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Xu Q, Shen L, Jin L, Wang M, Chang F, Guo Z. 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; 14:1582. [PMID: 35891562 PMCID: PMC9320214 DOI: 10.3390/v14071582] [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: 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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Affiliation(s)
- Qian Xu
- Correspondence: (Q.X.); (Z.G.)
| | | | | | | | | | - Zhongxin Guo
- 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; (L.S.); (L.J.); (M.W.); (F.C.)
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7
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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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8
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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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9
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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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10
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Guo H, Ge P, Tong J, Zhang Y, Peng X, Zhao Z, Ge F, Sun Y. Elevated Carbon Dioxide Levels Decreases Cucumber Mosaic Virus Accumulation in Correlation with Greater Accumulation of rgs-CaM, an Inhibitor of a Viral Suppressor of RNAi. PLANTS (BASEL, SWITZERLAND) 2020; 10:E59. [PMID: 33383811 PMCID: PMC7824600 DOI: 10.3390/plants10010059] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/23/2020] [Accepted: 12/25/2020] [Indexed: 11/16/2022]
Abstract
Plant viruses cause a range of plant diseases symptoms that are often responsible for significant crop production losses and the severity and spread of the symptoms may be affected by climate change. While the increase in anthropogenic activities has caused a critical problem of increased CO2 levels in the atmosphere, these elevated CO2 levels have been reported to reduce virus disease severity in some plant species. In such instances, it is not clear if the plant defense mechanisms are being enhanced or virus-mediated mechanisms to overcome plant resistance are being defeated. Additionally, a few studies have been attempted in this area to determine if reduced disease is the norm or the exception under enhanced CO2 levels. In the present study, the effects of elevated CO2 levels (750 ppm vs. 390 ppm) on RNAi-mediated resistance of Nicotiana tabacum against the cucumber mosaic virus (CMV), and the activity of viral suppressor of RNAi (VSR) 2b protein of CMV were evaluated. On the one hand, our results showed that elevated CO2 decreased the transcription of dicer-like protein 2 (DCL2), DCL4, and argonaut 1 (AGO1) genes with functions related to RNAi-mediated resistance when infected by CMV, which is contradictory with the decreased CMV copy numbers under elevated CO2. On the other hand, we found that elevated CO2 increased the calcium concentration and expression of the calcium-binding protein rgs-CaM in tobacco plants when infected by CMV, which directly weakened the function of 2b protein, the VSR of CMV, and therefore decreased the infection efficiency of the virus and suppressed the severity of CMV in tobacco plants under elevated CO2. This study provides molecular insights into the ecological implications underlying the development of prevention strategies against plant virus infection in the context of climate change.
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Affiliation(s)
- Huijuan Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (H.G.); (P.G.); (J.T.); (Y.Z.); (X.P.)
- CAS Center for Excellence in Biotic Interactions, Chinese Academy of Sciences, Beijing 100049, China
| | - Panpan Ge
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (H.G.); (P.G.); (J.T.); (Y.Z.); (X.P.)
| | - Jiahui Tong
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (H.G.); (P.G.); (J.T.); (Y.Z.); (X.P.)
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing 100193, China;
| | - Yanjing Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (H.G.); (P.G.); (J.T.); (Y.Z.); (X.P.)
| | - Xinhong Peng
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (H.G.); (P.G.); (J.T.); (Y.Z.); (X.P.)
- Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing 100193, China
| | - Zihua Zhao
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing 100193, China;
| | - Feng Ge
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (H.G.); (P.G.); (J.T.); (Y.Z.); (X.P.)
- CAS Center for Excellence in Biotic Interactions, Chinese Academy of Sciences, Beijing 100049, China
| | - Yucheng Sun
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (H.G.); (P.G.); (J.T.); (Y.Z.); (X.P.)
- CAS Center for Excellence in Biotic Interactions, Chinese Academy of Sciences, Beijing 100049, China
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11
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Jin Y, Zhao JH, Guo HS. Recent advances in understanding plant antiviral RNAi and viral suppressors of RNAi. Curr Opin Virol 2020; 46:65-72. [PMID: 33360834 DOI: 10.1016/j.coviro.2020.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 10/22/2022]
Abstract
Molecular plant-virus interactions provide an excellent model to understanding host antiviral immunity and viral counter-defense mechanisms. The primary antiviral defense is triggered inside the infected plant cell by virus-derived small-interfering RNAs, which guide homology-dependent RNA interference (RNAi) and/or RNA-directed DNA methylation (RdDM) to target RNA and DNA viruses. In counter-defense, plant viruses have independently evolved viral suppressors of RNAi (VSRs) to specifically antagonize antiviral RNAi. Recent studies have shown that plant antiviral responses are regulated by endogenous small silencing RNAs, RNA decay and autophagy and that some known VSRs of plant RNA and DNA viruses also target these newly recognized defense responses to promote infection. This review focuses on these recent advances that have revealed multilayered regulation of plant-virus interactions.
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Affiliation(s)
- Yun Jin
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing 100049, China.
| | - Jian-Hua Zhao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Hui-Shan Guo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing 100049, China
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12
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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. JOURNAL OF EXPERIMENTAL BOTANY 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] [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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13
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Cui C, Wang JJ, Zhao JH, Fang YY, He XF, Guo HS, Duan CG. A Brassica miRNA Regulates Plant Growth and Immunity through Distinct Modes of Action. MOLECULAR PLANT 2020; 13:231-245. [PMID: 31794845 DOI: 10.1016/j.molp.2019.11.010] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/12/2019] [Accepted: 11/26/2019] [Indexed: 05/18/2023]
Abstract
In plants, high disease resistance often results in a reduction of yield. Therefore, breeding crops with balanced yield and disease resistance has become a major challenge. Recently, microRNA (miRNA)-mediated R gene turnover has been shown to be a protective mechanism used by plants to prevent autoimmunity in the absence of pathogens. However, whether these miRNAs play a role in plant growth and how miRNA-mediated R gene turnover responds to pathogen infection have rarely been explored. Here, we found that a Brassica miRNA, miR1885, targets both an immune receptor gene and a development-related gene for negative regulation through distinct modes of action. MiR1885 directly silences the TIR-NBS-LRR class of R gene BraTNL1 but represses the expression of the photosynthesis-related gene BraCP24 by targeting the Trans-Acting Silencing (TAS) gene BraTIR1 for trans-acting small interfering RNAs (tasiRNAs)-mediated silencing. We found that, under natural conditions, miR1885 was kept at low levels to maintain normal development and basal immunity but peaked during the floral transition to promote flowering. Interestingly, upon Turnip mosaic virus (TuMV) infection, miR1885-dependent trans-acting silencing of BraCP24 was enhanced to speed up the floral transition, whereas miR1885-mediated R gene turnover was overcome by TuMV-induced BraTNL1 expression, reflecting precise regulation of the arms race between plants and pathogens. Collectively, our results demonstrate that a single Brassica miRNA dynamically regulates both innate immunity and plant growth and responds to viral infection, revealing that Brassica plants have developed a sophisticated mechanism in modulating the interplay between growth, immunity, and pathogen infection.
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Affiliation(s)
- Chen Cui
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jing-Jing Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Jian-Hua Zhao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan-Yuan Fang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiang-Feng He
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Hui-Shan Guo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing 100049, China.
| | - Cheng-Guo Duan
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China; State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China.
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14
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Xu M, Mazur MJ, Tao X, Kormelink R. Cellular RNA Hubs: Friends and Foes of Plant Viruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:40-54. [PMID: 31415225 DOI: 10.1094/mpmi-06-19-0161-fi] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
RNA granules are dynamic cellular foci that are widely spread in eukaryotic cells and play essential roles in cell growth and development, and immune and stress responses. Different types of granules can be distinguished, each with a specific function and playing a role in, for example, RNA transcription, modification, processing, decay, translation, and arrest. By means of communication and exchange of (shared) components, they form a large regulatory network in cells. Viruses have been reported to interact with one or more of these either cytoplasmic or nuclear granules, and act either proviral, to enable and support viral infection and facilitate viral movement, or antiviral, protecting or clearing hosts from viral infection. This review describes an overview and recent progress on cytoplasmic and nuclear RNA granules and their interplay with virus infection, first in animal systems and as a prelude to the status and current developments on plant viruses, which have been less well studied on this thus far.
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Affiliation(s)
- Min Xu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- Laboratory of Virology, Department of Plant Sciences, Wageningen University & Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
| | - Magdalena J Mazur
- Laboratory of Virology, Department of Plant Sciences, Wageningen University & Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
| | - Xiaorong Tao
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Richard Kormelink
- Laboratory of Virology, Department of Plant Sciences, Wageningen University & Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
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15
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Tzean Y, Lee MC, Jan HH, Chiu YS, Tu TC, Hou BH, Chen HM, Chou CN, Yeh HH. Cucumber mosaic virus-induced gene silencing in banana. Sci Rep 2019; 9:11553. [PMID: 31399618 PMCID: PMC6689018 DOI: 10.1038/s41598-019-47962-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/25/2019] [Indexed: 11/17/2022] Open
Abstract
Banana (Musa spp.) is one of the world's most important staple and cash crops. Despite accumulating genetic and transcriptomic data, low transformation efficiency in agronomically important Musa spp. render translational researches in banana difficult by using conventional knockout approaches. To develop tools for translational research in bananas, we developed a virus induced-gene silencing (VIGS) system based on a banana-infecting cucumber mosaic virus (CMV) isolate, CMV 20. CMV 20 genomic RNA 1, 2, and 3, were separately cloned in Agrobacterium pJL89 binary vectors, and a cloning site was introduced on RNA 2 immediately after the 2a open reading frame to insert the gene targeted for silencing. An efficient Agrobacterium inoculation method was developed for banana, which enabled the CMV 20 VIGS vector infection rate to reach 95% in our experiments. CMV 20-based silencing of Musa acuminata cv. Cavendish (AAA group) glutamate 1-semialdehyde aminotransferase (MaGSA) produced a typical chlorotic phenotype and silencing of M. acuminata phytoene desaturase (MaPDS) produced a photobleachnig phenotype. We show this approach efficiently reduced GSA and PDS transcripts to 10% and 18% of the control, respectively. The high infection rate and extended silencing of this VIGS system will provide an invaluable tool to accelerate functional genomic studies in banana.
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Affiliation(s)
- Yuh Tzean
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Section 2, Academia Road, Nankang District, Taipei, 11529, Taiwan
| | - Ming-Chi Lee
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Section 2, Academia Road, Nankang District, Taipei, 11529, Taiwan
| | - Hsiao-Hsuan Jan
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Section 2, Academia Road, Nankang District, Taipei, 11529, Taiwan
- Department of Plant Pathology and Microbiology, National Taiwan University, No. 1, Section 4, Roosevelt Road, Da'an District, Taipei, 10617, Taiwan
| | - Yi-Shu Chiu
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Section 2, Academia Road, Nankang District, Taipei, 11529, Taiwan
| | - Tsui-Chin Tu
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Section 2, Academia Road, Nankang District, Taipei, 11529, Taiwan
| | - Bo-Han Hou
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Section 2, Academia Road, Nankang District, Taipei, 11529, Taiwan
| | - Ho-Ming Chen
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Section 2, Academia Road, Nankang District, Taipei, 11529, Taiwan
| | - Chun-Nan Chou
- Department of Plant Pathology and Microbiology, National Taiwan University, No. 1, Section 4, Roosevelt Road, Da'an District, Taipei, 10617, Taiwan
| | - Hsin-Hung Yeh
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Section 2, Academia Road, Nankang District, Taipei, 11529, Taiwan.
- Department of Plant Pathology and Microbiology, National Taiwan University, No. 1, Section 4, Roosevelt Road, Da'an District, Taipei, 10617, Taiwan.
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16
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Soliman ERS, Meyer P. Responsiveness and Adaptation to Salt Stress of the REDOX-RESPONSIVE TRANSCRIPTION FACTOR 1 (RRTF1) Gene are Controlled by its Promoter. Mol Biotechnol 2019; 61:254-260. [PMID: 30734200 DOI: 10.1007/s12033-019-00155-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The REDOX-RESPONSIVE TRANSCRIPTION FACTOR 1 (RRTF1) gene encodes a member of the ERF/AP2 transcription factor family involved in redox homeostasis. The RRTF1 gene shows tissue-specific responsiveness to various abiotic stress treatments including a response to salt stress in roots. An interesting feature of this response is an adaptation phase that follows its activation, when promoter levels revert to a base line level, even if salt stress is maintained. It is unclear if adaption is controlled by a switch in promoter activity or by changes in transcript levels. Here we show that the RRTF1 promoter is sufficient for the control of both activation and adaptation to salt stress. As constitutive expression of RRTF1 turned out to be detrimental to the plant, we propose that promoter-regulated adaptation evolved as a protection mechanism to balance the beneficial effects of short-term gene activation and the detrimental effects of long-term gene expression.
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Affiliation(s)
- Elham R S Soliman
- Botany and Microbiology department, Faculty of Science, Helwan University, Cairo, Egypt.
| | - Peter Meyer
- Center for Plant Sciences, University of Leeds, Leeds, LS2 9JT, UK
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17
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Zheng X, Fahlgren N, Abbasi A, Berry JC, Carrington JC. Antiviral ARGONAUTEs Against Turnip Crinkle Virus Revealed by Image-Based Trait Analysis. PLANT PHYSIOLOGY 2019; 180:1418-1435. [PMID: 31043494 PMCID: PMC6752898 DOI: 10.1104/pp.19.00121] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/21/2019] [Indexed: 05/18/2023]
Abstract
RNA-based silencing functions as an important antiviral immunity mechanism in plants. Plant viruses evolved to encode viral suppressors of RNA silencing (VSRs) that interfere with the function of key components in the silencing pathway. As effectors in the RNA silencing pathway, ARGONAUTE (AGO) proteins are targeted by some VSRs, such as that encoded by Turnip crinkle virus (TCV). A VSR-deficient TCV mutant was used to identify AGO proteins with antiviral activities during infection. A quantitative phenotyping protocol using an image-based color trait analysis pipeline on the PlantCV platform, with temporal red, green, and blue imaging and a computational segmentation algorithm, was used to measure plant disease after TCV inoculation. This process captured and analyzed growth and leaf color of Arabidopsis (Arabidopsis thaliana) plants in response to virus infection over time. By combining this quantitative phenotypic data with molecular assays to detect local and systemic virus accumulation, AGO2, AGO3, and AGO7 were shown to play antiviral roles during TCV infection. In leaves, AGO2 and AGO7 functioned as prominent nonadditive, anti-TCV effectors, whereas AGO3 played a minor role. Other AGOs were required to protect inflorescence tissues against TCV. Overall, these results indicate that distinct AGO proteins have specialized, modular roles in antiviral defense across different tissues, and demonstrate the effectiveness of image-based phenotyping to quantify disease progression.
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Affiliation(s)
- Xingguo Zheng
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Noah Fahlgren
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Arash Abbasi
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Jeffrey C Berry
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
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18
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Guo H, Gu L, Liu F, Chen F, Ge F, Sun Y. Aphid-borne Viral Spread Is Enhanced by Virus-induced Accumulation of Plant Reactive Oxygen Species. PLANT PHYSIOLOGY 2019; 179:143-155. [PMID: 30381318 PMCID: PMC6324229 DOI: 10.1104/pp.18.00437] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 10/23/2018] [Indexed: 05/24/2023]
Abstract
Most known plant viruses are spread from plant to plant by insect vectors. There is strong evidence that nonpersistently transmitted viruses manipulate the release of plant volatiles to attract insect vectors, thereby promoting virus spread. The mechanisms whereby aphid settling and feeding is altered on plants infected with these viruses, however, are unclear. Here we employed loss-of-function mutations in cucumber mosaic virus (CMV) and one of its host plants, tobacco (Nicotiana tabacum), to elucidate such mechanisms. We show that, relative to a CMVΔ2b strain with a deletion of the viral suppressor of RNAi 2b protein in CMV, plants infected with wild-type CMV produce higher concentrations of the reactive oxygen species (ROS) H2O2 in plant tissues. Aphids on wild-type CMV-infected plants engage in shorter probes, less phloem feeding, and exhibit other changes, as detected by electrical penetration graphing technology, relative to CMVΔ2b-infected plants. Therefore, the frequency of virus acquisition and the virus load per aphid were greater on CMV-infected plants than on CMVΔ2b-infected plants. Aphids also moved away from initial feeding sites more frequently on wild-type CMV infected versus CMVΔ2b-infected plants. The role of H2O2 in eliciting these effects on aphids was corroborated using healthy plants infused with H2O2 Finally, H2O2 levels were not elevated, and aphid behavior was unchanged, on CMV-infected RbohD-silenced tobacco plants, which are deficient in the induction of ROS production. These results suggest that CMV uses its viral suppressor of RNAi protein to increase plant ROS levels, thereby enhancing its acquisition and transmission by vector insects.
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Affiliation(s)
- Huijuan Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Liyuan Gu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Fanqi Liu
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Fajun Chen
- University of Chinese Academy of Sciences, Beijing, China
| | - Feng Ge
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yucheng Sun
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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19
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Qi G, Chen J, Chang M, Chen H, Hall K, Korin J, Liu F, Wang D, Fu ZQ. Pandemonium Breaks Out: Disruption of Salicylic Acid-Mediated Defense by Plant Pathogens. MOLECULAR PLANT 2018; 11:1427-1439. [PMID: 30336330 DOI: 10.1016/j.molp.2018.10.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/30/2018] [Accepted: 10/09/2018] [Indexed: 05/26/2023]
Abstract
Salicylic acid (SA) or 2-hydroxybenoic acid is a phenolic plant hormone that plays an essential role in plant defense against biotrophic and semi-biotrophic pathogens. In Arabidopsis, SA is synthesized from chorismate in the chloroplast through the ICS1 (isochorismate synthase I) pathway during pathogen infection. The transcription co-activator NPR1 (Non-Expresser of Pathogenesis-Related Gene 1), as the master regulator of SA signaling, interacts with transcription factors to induce the expression of anti-microbial PR (Pathogenesis-Related) genes. To establish successful infections, plant bacterial, oomycete, fungal, and viral pathogens have evolved at least three major strategies to disrupt SA-mediated defense. The first strategy is to reduce SA accumulation directly by converting SA into its inactive derivatives. The second strategy is to interrupt SA biosynthesis by targeting the ICS1 pathway. In the third major strategy, plant pathogens deploy different mechanisms to interfere with SA downstream signaling. The wide array of strategies deployed by plant pathogens highlights the crucial role of disruption of SA-mediated plant defense in plant pathogenesis. A deeper understanding of this topic will greatly expand our knowledge of how plant pathogens cause diseases and consequently pave the way for the development of more effective ways to control these diseases.
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Affiliation(s)
- Guang Qi
- State Key Laboratory of Wheat and Maize Crop Science and College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Jian Chen
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing 210014, China; Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Ming Chang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing 210014, China; Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Huan Chen
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing 210014, China; Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Katherine Hall
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - John Korin
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Fengquan Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing 210014, China.
| | - Daowen Wang
- State Key Laboratory of Wheat and Maize Crop Science and College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China.
| | - Zheng Qing Fu
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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20
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CMV2b-Dependent Regulation of Host Defense Pathways in the Context of Viral Infection. Viruses 2018; 10:v10110618. [PMID: 30423959 PMCID: PMC6265714 DOI: 10.3390/v10110618] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 01/26/2023] Open
Abstract
RNA silencing (or RNA interference, RNAi) plays direct roles in plant host defenses against viruses. Viruses encode suppressors of RNAi (VSRs) to counteract host antiviral defenses. The generation of transgenic plants expressing VSRs facilitates the understanding of the mechanisms of VSR-mediated interference with the endogenous silencing pathway. However, studying VSRs independent of other viral components simplifies the complex roles of VSRs during natural viral infection. While suppression of transgene silencing by the VSR 2b protein encoded by cucumber mosaic virus (CMV) requires 2b-small RNA (sRNA) binding activity, suppression of host antiviral defenses requires the binding activity of both sRNAs and AGOs proteins. This study, aimed to understand the functions of 2b in the context of CMV infection; thus, we performed genome-wide analyses of differential DNA methylation regions among wild-type CMV-infected, CMVΔ2b-infected, and 2b-transgenic Arabidopsis plants. These analyses, together with transcriptome sequencing and RT-qPCR analyses, show that while the majority of induced genes in 2b-transgenic plants were involved in extensive metabolic pathways, CMV-infection 2b-dependent induced genes were enriched in plant immunity pathways, including salicylic acid (SA) signaling. Together with infection with CMV mutants that expressed the 2b functional domains of sRNA or AGO binding, our data demonstrate that CMV-accelerated SA signaling depends on 2b-sRNA binding activity which is also responsible for virulence.
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21
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Yang Z, Li Y. Dissection of RNAi-based antiviral immunity in plants. Curr Opin Virol 2018; 32:88-99. [PMID: 30388659 DOI: 10.1016/j.coviro.2018.08.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 08/03/2018] [Accepted: 08/05/2018] [Indexed: 10/28/2022]
Abstract
RNA interference (RNAi)-based antiviral defense is a small RNA-dependent repression mechanism of plants to against viruses. Although the core components of antiviral RNAi are well known, it is unclear whether additional factors exist that regulate RNAi. Recently, a forward genetic screen identified two novel components of antiviral RNAi, providing important insights into the antiviral RNAi mechanism. Meanwhile, it was discovered that microRNAs make important contributions to host antiviral RNAi. On the other hand, to counteract host antiviral RNAi, most viruses encode viral suppressors of RNA silencing (VSRs). Recent studies have revealed the multiple functions of VSRs and the intricate interactions between plant hosts and viruses. These findings add to our knowledge of the sophisticated host antiviral defense mechanism in plants. Ongoing molecular functional studies will improve our understanding of the co-evolutionary arms race between viruses and plants, and thereby provide key information for the development of plant antiviral strategies.
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Affiliation(s)
- Zhirui Yang
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yi Li
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.
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22
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Gupta AK, Hein GL, Graybosch RA, Tatineni S. Octapartite negative-sense RNA genome of High Plains wheat mosaic virus encodes two suppressors of RNA silencing. Virology 2018; 518:152-162. [PMID: 29499560 DOI: 10.1016/j.virol.2018.02.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 02/14/2018] [Accepted: 02/15/2018] [Indexed: 11/18/2022]
Abstract
High Plains wheat mosaic virus (HPWMoV, genus Emaravirus; family Fimoviridae), transmitted by the wheat curl mite (Aceria tosichella Keifer), harbors a monocistronic octapartite single-stranded negative-sense RNA genome. In this study, putative proteins encoded by HPWMoV genomic RNAs 2-8 were screened for potential RNA silencing suppression activity by using a green fluorescent protein-based reporter agroinfiltration assay. We found that proteins encoded by RNAs 7 (P7) and 8 (P8) suppressed silencing induced by single- or double-stranded RNAs and efficiently suppressed the transitive pathway of RNA silencing. Additionally, a Wheat streak mosaic virus (WSMV, genus Tritimovirus; family Potyviridae) mutant lacking the suppressor of RNA silencing (ΔP1) but having either P7 or P8 from HPWMoV restored cell-to-cell and long-distance movement in wheat, thus indicating that P7 or P8 rescued silencing suppressor-deficient WSMV. Furthermore, HPWMoV P7 and P8 substantially enhanced the pathogenicity of Potato virus X in Nicotiana benthamiana. Collectively, these data demonstrate that the octapartite genome of HPWMoV encodes two suppressors of RNA silencing.
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Affiliation(s)
- Adarsh K Gupta
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Gary L Hein
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Robert A Graybosch
- United States Department of Agriculture-Agricultural Research Service (USDA-ARS) and Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Satyanarayana Tatineni
- USDA-ARS and Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
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23
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Zhang XP, Liu DS, Yan T, Fang XD, Dong K, Xu J, Wang Y, Yu JL, Wang XB. Cucumber mosaic virus coat protein modulates the accumulation of 2b protein and antiviral silencing that causes symptom recovery in planta. PLoS Pathog 2017; 13:e1006522. [PMID: 28727810 PMCID: PMC5538744 DOI: 10.1371/journal.ppat.1006522] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/01/2017] [Accepted: 07/11/2017] [Indexed: 11/30/2022] Open
Abstract
Shoot apical meristems (SAM) are resistant to most plant viruses due to RNA silencing, which is restrained by viral suppressors of RNA silencing (VSRs) to facilitate transient viral invasion of the SAM. In many cases chronic symptoms and long-term virus recovery occur, but the underlying mechanisms are poorly understood. Here, we found that wild-type Cucumber mosaic virus (CMVWT) invaded the SAM transiently, but was subsequently eliminated from the meristems. Unexpectedly, a CMV mutant, designated CMVRA that harbors an alanine substitution in the N-terminal arginine-rich region of the coat protein (CP) persistently invaded the SAM and resulted in visible reductions in apical dominance. Notably, the CMVWT virus elicited more potent antiviral silencing than CMVRA in newly emerging leaves of infected plants. However, both viruses caused severe symptoms with minimal antiviral silencing effects in the Arabidopsis mutants lacking host RNA-DEPENDENT RNA POLYMERASE 6 (RDR6) or SUPPRESSOR OF GENE SILENCING 3 (SGS3), indicating that CMVWT induced host RDR6/SGS3-dependent antiviral silencing. We also showed that reduced accumulation of the 2b protein is elicited in the CMVWT infection and consequently rescues potent antiviral RNA silencing. Indeed, co-infiltration assays showed that the suppression of posttranscriptional gene silencing mediated by 2b is more severely compromised by co-expression of CPWT than by CPRA. We further demonstrated that CPWT had high RNA binding activity leading to translation inhibition in wheat germ systems, and CPWT was associated with SGS3 into punctate granules in vivo. Thus, we propose that the RNAs bound and protected by CPWT possibly serve as templates of RDR6/SGS3 complexes for siRNA amplification. Together, these findings suggest that the CMV CP acts as a central hub that modulates antiviral silencing and VSRs activity, and mediates viral self-attenuation and long-term symptom recovery.
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Affiliation(s)
- Xiao-Peng Zhang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - De-Shui Liu
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Teng Yan
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xiao-Dong Fang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Kai Dong
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jin Xu
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Ying Wang
- College of Plant Protection, China Agricultural University, Beijing, China
| | - Jia-Lin Yu
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xian-Bing Wang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
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