1
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Kim H, Kawakubo S, Takahashi H, Masuta C. Two mutually exclusive evolutionary scenarios for allexiviruses that overcome host RNA silencing and autophagy by regulating viral CRP expression. PLoS Pathog 2023; 19:e1011457. [PMID: 37379324 DOI: 10.1371/journal.ppat.1011457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 06/02/2023] [Indexed: 06/30/2023] Open
Abstract
The genus Allexivirus currently includes eight virus species that infect allium plants. Previously, we showed that there are two distinct groups of allexiviruses (deletion [D]-type and insertion [I]-type) based on the presence or absence of a 10- to 20-base insert (IS) between the coat protein (CP) and cysteine rich protein (CRP) genes. In the present study of CRPs to analyze their functions, we postulated that evolution of allexiviruses may have been largely directed by CRPs and thus proposed two evolutionary scenarios for allexiviruses based mainly on the presence or absence of IS and determined by how the allexiviruses challenge host resistance mechanisms (RNA silencing and autophagy). We found that both CP and CRP are RNA silencing suppressors (RSS), that they can inhibit each other's RSS activity in the cytoplasm, and that CRP becomes a target of host autophagy in the cytoplasm but not CP. To mitigate CRP interference with CP, and to increase the CP's RSS activity, allexiviruses developed two strategies: confinement of D-type CRP in the nucleus and degradation of I-type CRP by autophagy in the cytoplasm. Here, we demonstrate that viruses of the same genus achieve two completely different evolutionary scenarios by controlling expression and subcellular localization of CRP.
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Affiliation(s)
- Hangil Kim
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, Japan
| | - Shusuke Kawakubo
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, Japan
| | - Haruna Takahashi
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, Japan
| | - Chikara Masuta
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, Japan
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Brioudes F, Jay F, Voinnet O. Suppression of both intra- and intercellular RNA silencing by the tombusviral P19 protein requires its small RNA binding property. THE NEW PHYTOLOGIST 2022; 235:824-829. [PMID: 35686966 PMCID: PMC9328354 DOI: 10.1111/nph.18180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 04/19/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Florian Brioudes
- Department of BiologyETH‐ZürichUniversitätsstrasse 2Zürich8092Switzerland
| | - Florence Jay
- Department of BiologyETH‐ZürichUniversitätsstrasse 2Zürich8092Switzerland
| | - Olivier Voinnet
- Department of BiologyETH‐ZürichUniversitätsstrasse 2Zürich8092Switzerland
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Rattan UK, Kumar S, Kumari R, Bharti M, Hallan V. Homeobox 27, a Homeodomain Transcription Factor, Confers Tolerances to CMV by Associating with Cucumber Mosaic Virus 2b Protein. Pathogens 2022; 11:pathogens11070788. [PMID: 35890032 PMCID: PMC9323240 DOI: 10.3390/pathogens11070788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/06/2022] [Accepted: 07/06/2022] [Indexed: 11/16/2022] Open
Abstract
Transcription factors (TFs) play an important role in plant development; however, their role during viral infection largely remains unknown. The present study was designed to uncover the role transcription factors play in Cucumber mosaic virus (CMV) infection. During the screening of an Arabidopsis thaliana (Col-0) transcription factor library, using the CMV 2b protein as bait in the yeast two-hybrid system, the 2b protein interacted with Homeobox protein 27 (HB27). HB27 belongs to the zinc finger homeodomain family and is known to have a regulatory role in flower development, and responses to biotic and abiotic stress. The interaction between CMV 2b and HB27 proteins was further validated using in planta (bimolecular fluorescence complementation assay) and in vitro far-Western blotting (FWB) methods. In the bimolecular fluorescence complementation assay, these proteins reconstituted YFP fluorescence in the nucleus and the cytoplasmic region as small fluorescent dots. In FWB, positive interaction was detected using bait anti-MYC antibody on the target HB27-HA protein. During CMV infection, upregulation (~3-fold) of the HB27 transcript was observed at 14 days post-infection (dpi) in A. thaliana plants, and expression declined to the same as healthy plants at 21 dpi. To understand the role of the HB27 protein during CMV infection, virus accumulation was determined in HB27-overexpressing (HB27 OE) and knockout mutants. In HB27-overexpressing lines, infected plants developed mild symptoms, accumulating a lower virus titer at 21 dpi compared to wild-type plants. Additionally, knockout HB27 mutants had more severe symptoms and a higher viral accumulation than wild-type plants. These results indicate that HB27 plays an important role in the regulation of plant defense against plant virus infection.
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Affiliation(s)
- Usha Kumari Rattan
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Surender Kumar
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
| | - Reenu Kumari
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
- College of Horticulture and Forestry, Dr. Y. S. Parmar University of Horticulture and Forestry, Thunag, Mandi 175048, India
| | - Monika Bharti
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
| | - Vipin Hallan
- Plant Virology Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India; (U.K.R.); (S.K.); (R.K.); (M.B.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Correspondence: ; Tel.: +91-1894-233338; Fax: +91-1894-230433
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Zhang C, Wang X, Li H, Wang J, Zeng Q, Huang W, Huang H, Xie Y, Yu S, Kan Q, Wang Q, Cheng Y. GLRaV-2 protein p24 suppresses host defenses by interaction with a RAV transcription factor from grapevine. PLANT PHYSIOLOGY 2022; 189:1848-1865. [PMID: 35485966 PMCID: PMC9237672 DOI: 10.1093/plphys/kiac181] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/24/2022] [Indexed: 05/27/2023]
Abstract
Grapevine leafroll-associated virus 2 (GLRaV-2) is a prevalent virus associated with grapevine leafroll disease, but the molecular mechanism underlying GLRaV-2 infection is largely unclear. Here, we report that 24-kDa protein (p24), an RNA-silencing suppressor (RSS) encoded by GLRaV-2, promotes GLRaV-2 accumulation via interaction with the B3 DNA-binding domain of grapevine (Vitis vinifera) RELATED TO ABSCISIC ACID INSENSITIVE3/VIVIPAROUS1 (VvRAV1), a transcription factor belonging to the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) superfamily. Salicylic acid-inducible VvRAV1 positively regulates the grapevine pathogenesis-related protein 1 (VvPR1) gene by directly binding its promoter, indicating that VvRAV1 may function in the regulation of host basal defense responses. p24 hijacks VvRAV1 to the cytoplasm and employs the protein to sequester 21-nt double-stranded siRNA together, thereby enhancing its own RSS activity. Moreover, p24 enters the nucleus via interaction with VvRAV1 and weakens the latter's binding affinity to the VvPR1 promoter, leading to decreased expression of VvPR1. Our results provide a mechanism by which a viral RSS interferes with both the antiviral RNA silencing and the AP2/ERF-mediated defense responses via the targeting of one specific host factor.
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Affiliation(s)
| | - Xianyou Wang
- Department of Pomology/Lab of Stress Physiology and Molecular Biology for Tree Fruits, Key Lab of Beijing Municipality, China Agricultural University, Beijing 100193, China
| | - Hanwei Li
- Department of Pomology/Lab of Stress Physiology and Molecular Biology for Tree Fruits, Key Lab of Beijing Municipality, China Agricultural University, Beijing 100193, China
| | - Jinying Wang
- Department of Pomology/Lab of Stress Physiology and Molecular Biology for Tree Fruits, Key Lab of Beijing Municipality, China Agricultural University, Beijing 100193, China
| | - Qi Zeng
- Department of Pomology/Lab of Stress Physiology and Molecular Biology for Tree Fruits, Key Lab of Beijing Municipality, China Agricultural University, Beijing 100193, China
| | - Wenting Huang
- Department of Pomology/Lab of Stress Physiology and Molecular Biology for Tree Fruits, Key Lab of Beijing Municipality, China Agricultural University, Beijing 100193, China
| | - Haoqiang Huang
- Department of Pomology/Lab of Stress Physiology and Molecular Biology for Tree Fruits, Key Lab of Beijing Municipality, China Agricultural University, Beijing 100193, China
| | - Yinshuai Xie
- Department of Pomology/Lab of Stress Physiology and Molecular Biology for Tree Fruits, Key Lab of Beijing Municipality, China Agricultural University, Beijing 100193, China
| | - Shangzhen Yu
- Department of Pomology/Lab of Stress Physiology and Molecular Biology for Tree Fruits, Key Lab of Beijing Municipality, China Agricultural University, Beijing 100193, China
| | - Qing Kan
- Department of Pomology/Lab of Stress Physiology and Molecular Biology for Tree Fruits, Key Lab of Beijing Municipality, China Agricultural University, Beijing 100193, China
| | - Qi Wang
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
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Xia YH, Ding BJ, Dong SL, Wang HL, Hofvander P, Löfstedt C. Release of moth pheromone compounds from Nicotiana benthamiana upon transient expression of heterologous biosynthetic genes. BMC Biol 2022; 20:80. [PMID: 35361182 PMCID: PMC8969271 DOI: 10.1186/s12915-022-01281-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 03/12/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Using genetically modified plants as natural dispensers of insect pheromones may eventually become part of a novel strategy for integrated pest management. RESULTS In the present study, we first characterized essential functional genes for sex pheromone biosynthesis in the rice stem borer Chilo suppressalis (Walker) by heterologous expression in Saccharomyces cerevisiae and Nicotiana benthamiana, including two desaturase genes CsupYPAQ and CsupKPSE and a reductase gene CsupFAR2. Subsequently, we co-expressed CsupYPAQ and CsupFAR2 together with the previously characterized moth desaturase Atr∆11 in N. benthamiana. This resulted in the production of (Z)-11-hexadecenol together with (Z)-11-hexadecenal, the major pheromone component of C. suppressalis. Both compounds were collected from the transformed N. benthamiana headspace volatiles using solid-phase microextraction. We finally added the expression of a yeast acetyltransferase gene ATF1 and could then confirm also (Z)-11-hexadecenyl acetate release from the plant. CONCLUSIONS Our results pave the way for stable transformation of plants to be used as biological pheromone sources in different pest control strategies.
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Affiliation(s)
- Yi-Han Xia
- Department of Biology, Lund University, Sölvegatan 37, SE-22362, Lund, Sweden
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 4, SE-41296, Gothenburg, Sweden
| | - Bao-Jian Ding
- Department of Biology, Lund University, Sölvegatan 37, SE-22362, Lund, Sweden
| | - Shuang-Lin Dong
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, CN-210095, China
| | - Hong-Lei Wang
- Department of Biology, Lund University, Sölvegatan 37, SE-22362, Lund, Sweden
| | - Per Hofvander
- Department of Plant Breeding, Swedish University of Agricultural Sciences, P.O. Box 101, SE-23053, Alnarp, Sweden
| | - Christer Löfstedt
- Department of Biology, Lund University, Sölvegatan 37, SE-22362, Lund, Sweden.
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A fungal effector suppresses the nuclear export of AGO1-miRNA complex to promote infection in plants. Proc Natl Acad Sci U S A 2022; 119:e2114583119. [PMID: 35290117 PMCID: PMC8944911 DOI: 10.1073/pnas.2114583119] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
SignificanceIncreasing evidence demonstrates that small RNAs can serve as trafficking effectors to mediate bidirectional transkingdom RNA interference (RNAi) in interacting organisms, including plant-pathogenic fungi systems. Previous findings demonstrated that plants can send microRNAs (miRNAs) to fungal pathogen Verticillium dahliae to trigger antifungal RNAi. Here we report that V. dahliae is able to secret an effector to the plant nucleus to interfere with the nuclear export of AGO1-miRNA complexes, leading to an inhibition in antifungal RNAi and increased virulence in plants. Thus, we reveal an antagonistic mechanism that can be exploited by fungal pathogens to counteract antifungal RNAi immunity via manipulation of plant small RNA function.
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7
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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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8
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Hinge VR, Chavhan RL, Kale SP, Suprasanna P, Kadam US. Engineering Resistance Against Viruses in Field Crops Using CRISPR- Cas9. Curr Genomics 2021; 22:214-231. [PMID: 34975291 PMCID: PMC8640848 DOI: 10.2174/1389202922666210412102214] [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: 10/06/2020] [Revised: 01/29/2021] [Accepted: 02/24/2021] [Indexed: 12/26/2022] Open
Abstract
Food security is threatened by various biotic stresses that affect the growth and production of agricultural crops. Viral diseases have become a serious concern for crop plants as they incur huge yield losses. The enhancement of host resistance against plant viruses is a priority for the effective management of plant viral diseases. However, in the present context of the climate change scenario, plant viruses are rapidly evolving, resulting in the loss of the host resistance mechanism. Advances in genome editing techniques, such as CRISPR-Cas9 [clustered regularly interspaced palindromic repeats-CRISPR-associated 9], have been recognized as promising tools for the development of plant virus resistance. CRISPR-Cas9 genome editing tool is widely preferred due to high target specificity, simplicity, efficiency, and reproducibility. CRISPR-Cas9 based virus resistance in plants has been successfully achieved by gene targeting and cleaving the viral genome or altering the plant genome to enhance plant innate immunity. In this article, we have described the CRISPR-Cas9 system, mechanism of plant immunity against viruses and highlighted the use of the CRISPR-Cas9 system to engineer virus resistance in plants. We also discussed prospects and challenges on the use of CRISPR-Cas9-mediated plant virus resistance in crop improvement.
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Affiliation(s)
- Vidya R Hinge
- 1Department of Plant Biotechnology, Vilasrao Deshmukh College of Agricultural Biotechnology, Latur; Vasantrao Naik Marathwada Krishi Vidyapeeth (VNMKV), Parbhani 431 402, India; 2USAID-BIRAC International Project, School of Life Sciences, S.R.T.M.U., Nanded, India; 3Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400 085, India; 4Max Planck Institute of Molecular Plant Physiology, Potsdam- Golm, 14476, Germany
| | - Rahul L Chavhan
- 1Department of Plant Biotechnology, Vilasrao Deshmukh College of Agricultural Biotechnology, Latur; Vasantrao Naik Marathwada Krishi Vidyapeeth (VNMKV), Parbhani 431 402, India; 2USAID-BIRAC International Project, School of Life Sciences, S.R.T.M.U., Nanded, India; 3Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400 085, India; 4Max Planck Institute of Molecular Plant Physiology, Potsdam- Golm, 14476, Germany
| | - Sandeep P Kale
- 1Department of Plant Biotechnology, Vilasrao Deshmukh College of Agricultural Biotechnology, Latur; Vasantrao Naik Marathwada Krishi Vidyapeeth (VNMKV), Parbhani 431 402, India; 2USAID-BIRAC International Project, School of Life Sciences, S.R.T.M.U., Nanded, India; 3Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400 085, India; 4Max Planck Institute of Molecular Plant Physiology, Potsdam- Golm, 14476, Germany
| | - Penna Suprasanna
- 1Department of Plant Biotechnology, Vilasrao Deshmukh College of Agricultural Biotechnology, Latur; Vasantrao Naik Marathwada Krishi Vidyapeeth (VNMKV), Parbhani 431 402, India; 2USAID-BIRAC International Project, School of Life Sciences, S.R.T.M.U., Nanded, India; 3Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400 085, India; 4Max Planck Institute of Molecular Plant Physiology, Potsdam- Golm, 14476, Germany
| | - Ulhas S Kadam
- 1Department of Plant Biotechnology, Vilasrao Deshmukh College of Agricultural Biotechnology, Latur; Vasantrao Naik Marathwada Krishi Vidyapeeth (VNMKV), Parbhani 431 402, India; 2USAID-BIRAC International Project, School of Life Sciences, S.R.T.M.U., Nanded, India; 3Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400 085, India; 4Max Planck Institute of Molecular Plant Physiology, Potsdam- Golm, 14476, Germany
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9
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Navarro JA, Saiz-Bonilla M, Sanchez-Navarro JA, Pallas V. The mitochondrial and chloroplast dual targeting of a multifunctional plant viral protein modulates chloroplast-to-nucleus communication, RNA silencing suppressor activity, encapsidation, pathogenesis and tissue tropism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:197-218. [PMID: 34309112 DOI: 10.1111/tpj.15435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/19/2021] [Indexed: 05/22/2023]
Abstract
Plant defense against melon necrotic spot virus (MNSV) is triggered by the viral auxiliary replicase p29 that is targeted to mitochondrial membranes causing morphological alterations, oxidative burst and necrosis. Here we show that MNSV coat protein (CP) was also targeted to mitochondria and mitochondrial-derived replication complexes [viral replication factories or complex (VRC)], in close association with p29, in addition to chloroplasts. CP import resulted in the cleavage of the R/arm domain previously implicated in genome binding during encapsidation and RNA silencing suppression (RSS). We also show that CP organelle import inhibition enhanced RSS activity, CP accumulation and VRC biogenesis but resulted in inhibition of systemic spreading, indicating that MNSV whole-plant infection requires CP organelle import. We hypothesize that to alleviate the p29 impact on host physiology, MNSV could moderate its replication and p29 accumulation by regulating CP RSS activity through organelle targeting and, consequently, eluding early-triggered antiviral response. Cellular and molecular events also suggested that S/P domains, which correspond to processed CP in chloroplast stroma or mitochondrion matrix, could mitigate host response inhibiting p29-induced necrosis. S/P deletion mainly resulted in a precarious balance between defense and counter-defense responses, generating either cytopathic alterations and MNSV cell-to-cell movement restriction or some degree of local movement. In addition, local necrosis and defense responses were dampened when RSS activity but not S/P organelle targeting was affected. Based on a robust biochemical and cellular analysis, we established that the mitochondrial and chloroplast dual targeting of MNSV CP profoundly impacts the viral infection cycle.
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Affiliation(s)
- Jose A Navarro
- Department of Molecular and Evolutionary Plant Virology, Institute for Plant Molecular and Cell Biology, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, Av. Ingeniero Fausto Elio, Valencia, 46022, Spain
| | - Maria Saiz-Bonilla
- Department of Molecular and Evolutionary Plant Virology, Institute for Plant Molecular and Cell Biology, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, Av. Ingeniero Fausto Elio, Valencia, 46022, Spain
| | - Jesus A Sanchez-Navarro
- Department of Molecular and Evolutionary Plant Virology, Institute for Plant Molecular and Cell Biology, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, Av. Ingeniero Fausto Elio, Valencia, 46022, Spain
| | - Vicente Pallas
- Department of Molecular and Evolutionary Plant Virology, Institute for Plant Molecular and Cell Biology, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, Av. Ingeniero Fausto Elio, Valencia, 46022, Spain
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10
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Changes in Subcellular Localization of Host Proteins Induced by Plant Viruses. Viruses 2021; 13:v13040677. [PMID: 33920930 PMCID: PMC8071230 DOI: 10.3390/v13040677] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/08/2021] [Accepted: 04/12/2021] [Indexed: 12/24/2022] Open
Abstract
Viruses are dependent on host factors at all parts of the infection cycle, such as translation, genome replication, encapsidation, and cell-to-cell and systemic movement. RNA viruses replicate their genome in compartments associated with the endoplasmic reticulum, chloroplasts, and mitochondria or peroxisome membranes. In contrast, DNA viruses replicate in the nucleus. Viral infection causes changes in plant gene expression and in the subcellular localization of some host proteins. These changes may support or inhibit virus accumulation and spread. Here, we review host proteins that change their subcellular localization in the presence of a plant virus. The most frequent change is the movement of host cytoplasmic proteins into the sites of virus replication through interactions with viral proteins, and the protein contributes to essential viral processes. In contrast, only a small number of studies document changes in the subcellular localization of proteins with antiviral activity. Understanding the changes in the subcellular localization of host proteins during plant virus infection provides novel insights into the mechanisms of plant–virus interactions and may help the identification of targets for designing genetic resistance to plant viruses.
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11
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Yoon JY, Palukaitis P. Cucumber Mosaic Virus 1a Protein Interacts with the Tobacco SHE1 Transcription Factor and Partitions between the Nucleus and the Tonoplast Membrane. THE PLANT PATHOLOGY JOURNAL 2021; 37:182-193. [PMID: 33866760 PMCID: PMC8053847 DOI: 10.5423/ppj.ft.03.2021.0045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 03/14/2021] [Indexed: 06/12/2023]
Abstract
The transcription factor SHE1 was identified as an interacting partner with the cucumber mosaic virus (CMV) 1a protein in the yeast two-hybrid system, by a pull-down assay, and via bimolecular fluorescent complementation. Using fluorescent-tagged proteins and confocal microscopy, the CMV 1a protein itself was found distributed predominantly between the nucleus and the tonoplast membrane, although it was also found in speckles in the cytoplasm. The SHE1 protein was localized in the nucleus, but in the presence of the CMV 1a protein was partitioned between the nucleus and the tonoplast membrane. SHE1 expression was induced by infection of tobacco with four tested viruses: CMV, tobacco mosaic virus, potato virus X and potato virus Y. Transgenic tobacco expressing the CMV 1a protein showed constitutive expression of SHE1, indicating that the CMV 1a protein may be responsible for its induction. However, previously, such plants also were shown to have less resistance to local and systemic movement of tobacco mosaic virus (TMV) expressing the green fluorescent protein, suggesting that the CMV 1a protein may act to prevent the function of the SHE1 protein. SHE1 is a member of the AP2/ERF class of transcription factors and is conserved in sequence in several Nicotiana species, although two clades of SHE1 could be discerned, including both different Nicotiana species and cultivars of tobacco, varying by the presence of particular insertions or deletions.
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Affiliation(s)
- Ju-Yeon Yoon
- Virology Unit, Division of Horticultural and Herbal Crop Environment, National Institute of Horticultural and Herbal Science, Rural Development Administration, Wanju 55365,
Korea
| | - Peter Palukaitis
- Department of Horticulture Sciences, Seoul Women's University, Seoul 01797,
Korea
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12
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Jiang L, Lu Y, Zheng X, Yang X, Chen Y, Zhang T, Zhao X, Wang S, Zhao X, Song X, Zhang X, Peng J, Zheng H, Lin L, MacFarlane S, Liu Y, Chen J, Yan F. The plant protein NbP3IP directs degradation of Rice stripe virus p3 silencing suppressor protein to limit virus infection through interaction with the autophagy-related protein NbATG8. THE NEW PHYTOLOGIST 2021; 229:1036-1051. [PMID: 32898938 DOI: 10.1111/nph.16917] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 06/02/2020] [Indexed: 05/06/2023]
Abstract
In plants, autophagy is involved in responses to viral infection. However, the role of host factors in mediating autophagy to suppress viruses is poorly understood. A previously uncharacterized plant protein, NbP3IP, was shown to interact with p3, an RNA-silencing suppressor protein encoded by Rice stripe virus (RSV), a negative-strand RNA virus. The potential roles of NbP3IP in RSV infection were examined. NbP3IP degraded p3 through the autophagy pathway, thereby affecting the silencing suppression activity of p3. Transgenic overexpression of NbP3IP conferred resistance to RSV infection in Nicotiana benthamiana. RSV infection was promoted in ATG5- or ATG7-silenced plants and was inhibited in GAPC-silenced plants where autophagy was activated, confirming the role of autophagy in suppressing RSV infection. NbP3IP interacted with NbATG8f, indicating a potential selective autophagosomal cargo receptor role for P3IP. Additionally, the rice NbP3IP homolog (OsP3IP) also mediated p3 degradation and interacted with OsATG8b and p3. Through identification of the involvement of P3IP in the autophagy-mediated degradation of RSV p3, we reveal a new mechanism to antagonize the infection of RSV, and thereby provide the first evidence that autophagy can play an antiviral role against negative-strand RNA viruses.
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Affiliation(s)
- Liangliang Jiang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Yuwen Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
- Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Xiyin Zheng
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xue Yang
- College of Plant Protection, Shenyang Agriculture University, Shenyang, 110161, China
| | - Ying Chen
- College of Plant Protection, Shenyang Agriculture University, Shenyang, 110161, China
| | - Tianhao Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Xing Zhao
- College of Plant Protection, Shenyang Agriculture University, Shenyang, 110161, China
| | - Shu Wang
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Xia Zhao
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xijiao Song
- Public Lab, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Xiangxiang Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Jiejun Peng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
- Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Hongying Zheng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
- Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Lin Lin
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
- Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Stuart MacFarlane
- Cell and Molecular Sciences Group, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
| | - Yule Liu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jianping Chen
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
- Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Fei Yan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
- Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
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13
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Watt LG, Crawshaw S, Rhee SJ, Murphy AM, Canto T, Carr JP. The cucumber mosaic virus 1a protein regulates interactions between the 2b protein and ARGONAUTE 1 while maintaining the silencing suppressor activity of the 2b protein. PLoS Pathog 2020; 16:e1009125. [PMID: 33270799 PMCID: PMC7738167 DOI: 10.1371/journal.ppat.1009125] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 12/15/2020] [Accepted: 11/04/2020] [Indexed: 12/30/2022] Open
Abstract
The cucumber mosaic virus (CMV) 2b viral suppressor of RNA silencing (VSR) is a potent counter-defense and pathogenicity factor that inhibits antiviral silencing by titration of short double-stranded RNAs. It also disrupts microRNA-mediated regulation of host gene expression by binding ARGONAUTE 1 (AGO1). But in Arabidopsis thaliana complete inhibition of AGO1 is counterproductive to CMV since this triggers another layer of antiviral silencing mediated by AGO2, de-represses strong resistance against aphids (the insect vectors of CMV), and exacerbates symptoms. Using confocal laser scanning microscopy, bimolecular fluorescence complementation, and co-immunoprecipitation assays we found that the CMV 1a protein, a component of the viral replicase complex, regulates the 2b-AGO1 interaction. By binding 2b protein molecules and sequestering them in P-bodies, the 1a protein limits the proportion of 2b protein molecules available to bind AGO1, which ameliorates 2b-induced disease symptoms, and moderates induction of resistance to CMV and to its aphid vector. However, the 1a protein-2b protein interaction does not inhibit the ability of the 2b protein to inhibit silencing of reporter gene expression in agroinfiltration assays. The interaction between the CMV 1a and 2b proteins represents a novel regulatory system in which specific functions of a VSR are selectively modulated by another viral protein. The finding also provides a mechanism that explains how CMV, and possibly other viruses, modulates symptom induction and manipulates host-vector interactions.
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Affiliation(s)
- Lewis G. Watt
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Sam Crawshaw
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Sun-Ju Rhee
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Alex M. Murphy
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Tomás Canto
- Department of Microbial and Plant Biotechnology, Center for Biological Research, Madrid, Spain
| | - John P. Carr
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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14
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Yang X, Tian Y, Zhao X, Jiang L, Chen Y, Hu S, MacFarlane S, Chen J, Lu Y, Yan F. NbALY916 is involved in potato virus X P25-triggered cell death in Nicotiana benthamiana. MOLECULAR PLANT PATHOLOGY 2020; 21:1495-1501. [PMID: 32893420 PMCID: PMC7549001 DOI: 10.1111/mpp.12986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 08/04/2020] [Accepted: 08/04/2020] [Indexed: 06/11/2023]
Abstract
Systemic necrosis often occurs during viral infection of plants and is thought mainly to be the result of long-term stress induced by viral infection. Potato virus X (PVX) encodes the P25 pathogenicity factor that triggers a necrotic reaction during PVX-potato virus Ysynergistic coinfection. In this study, we discovered that NbALY916, a multifunctional nuclear protein, could interact with P25. When NbALY916 expression was reduced by tobacco rattle virus (TRV)-based virus-induced gene silencing, the accumulation of P25 was increased, which would be expected to cause more severe necrosis. However, silencing of NbALY916 reduced the extent of cell death caused by P25. Furthermore, we found that overexpression of NbALY916 increased the accumulation of H2 O2 and triggered more extensive cell death when coexpressed with P25, even though accumulation of P25 was itself reduced by the increased expression of NbALY916. Furthermore, transient expression of P25 specifically induced the expression of NbALY916 mRNA, but not the mRNAs of three other ALYs in Nicotiana benthamiana. In addition, we showed that silencing of NbALY916 or transient overexpression of NbALY916 affected the infection of PVX in N. benthamiana. Our results reveal that NbALY916 has an antiviral role that, in the case of PVX, operates by inducing the accumulation of H2 O2 and mediating the degradation of P25.
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Affiliation(s)
- Xue Yang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro‐productsKey Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang ProvinceInstitute of Plant VirologyNingbo UniversityNingboChina
- College of Plant ProtectionHenan Agriculture UniversityZhengzhouChina
| | - Yanzhen Tian
- College of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | - Xing Zhao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro‐productsKey Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang ProvinceInstitute of Plant VirologyNingbo UniversityNingboChina
| | - Liangliang Jiang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro‐productsKey Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang ProvinceInstitute of Plant VirologyNingbo UniversityNingboChina
| | - Ying Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro‐productsKey Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang ProvinceInstitute of Plant VirologyNingbo UniversityNingboChina
| | - Shuzhen Hu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro‐productsKey Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang ProvinceInstitute of Plant VirologyNingbo UniversityNingboChina
| | - Stuart MacFarlane
- The James Hutton Institute, Cell and Molecular Sciences GroupInvergowrie, DundeeUK
| | - Jianping Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro‐productsKey Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang ProvinceInstitute of Plant VirologyNingbo UniversityNingboChina
| | - Yuwen Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro‐productsKey Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang ProvinceInstitute of Plant VirologyNingbo UniversityNingboChina
| | - Fei Yan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro‐productsKey Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang ProvinceInstitute of Plant VirologyNingbo UniversityNingboChina
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15
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Freire MÁ. Viral silencing suppressors and cellular proteins partner with plant RRP6-like exoribonucleases. Virus Genes 2020; 56:621-631. [PMID: 32519287 DOI: 10.1007/s11262-020-01775-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 06/02/2020] [Indexed: 10/24/2022]
Abstract
RNA silencing and RNA decay are functionally interlaced, regulate gene expression and play a pivotal role in antiviral responses. As a counter-defensive strategy, many plant and mammalian viruses encode suppressors which interfere with both mechanisms. However, the protein interactions that connect these pathways remain elusive. Previous work reported that RNA silencing suppressors from different potyviruses, together with translation initiation factors EIF(iso)4E, interacted with the C-terminal region of the tobacco exoribonuclease RRP6-like 2, a component of the RNA decay exosome complex. Here, we investigate whether other viral silencing suppressors and cellular proteins might also bind RRP6-like exoribonucleases. A candidate search approach based on yeast two-hybrid protein interaction assays showed that three other unrelated viral suppressors, two from plant viruses and one from a mammalian virus, bound the C-terminus of the tobacco RRP6-like 2, the full-length of the Arabidopsis RRP6L1 protein and its C-terminal region. In addition, RRP6-like proteins were found to interact with members of the cellular double-stranded RNA-binding protein (DRB) family involved in RNA silencing. The C-terminal regions of RRP6L proteins are engaged in homotypic and heterotypic interactions and were predicted to be disordered. Collectively, these results suggest a protein interaction network that connects components of RNA decay and RNA silencing that is targeted by viral silencing suppressors.
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Affiliation(s)
- Miguel Ángel Freire
- Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET, Universidad Nacional de Córdoba (UNC), Av. Vélez Sarsfield 299, CC 495, 5000, Córdoba, Argentina.
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16
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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:ijms21197241. [PMID: 33008056 PMCID: PMC7583044 DOI: 10.3390/ijms21197241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [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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17
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Yang T, Qiu L, Huang W, Xu Q, Zou J, Peng Q, Lin H, Xi D. Chilli veinal mottle virus HCPro interacts with catalase to facilitate virus infection in Nicotiana tabacum. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:5656-5668. [PMID: 32594157 PMCID: PMC7501817 DOI: 10.1093/jxb/eraa304] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 06/19/2020] [Indexed: 05/06/2023]
Abstract
Plant symptoms are derived from specific interactions between virus and host components. However, little is known about viral or host factors that participate in the establishment of systemic necrosis. Here, we showed that helper component proteinase (HCPro), encoded by Chilli veinal mottle virus (ChiVMV), could directly interact with catalase 1 (CAT1) and catalase 3 (CAT3) in the cytoplasm of tobacco (Nicotiana tabacum) plants to facilitate viral infection. In vitro, the activities of CAT1 and CAT3 were inhibited by the interaction between HCPro and CATs. The C-terminus of HCPro was essential for their interaction and was also required for the decrease of enzyme activities. Interestingly, the mRNA and protein level of CATs were up-regulated in tobacco plants in response to ChiVMV infection. Nicotiana tabacum plants with HCPro overexpression or CAT1 knockout were more susceptible to ChiVMV infection, which was similar to the case of H2O2-pre-treated plants, and the overexpression of CAT1 inhibited ChiVMV accumulation. Also, neither CAT1 nor CAT3 could affect the RNA silencing suppression (RSS) activity of HCPro. Our results showed that the interaction between HCPro and CATs promoted the development of plant systemic necrosis, revealing a novel role for HCPro in virus infection and pathogenicity.
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Affiliation(s)
- Ting Yang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, PR China
| | - Long Qiu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, PR China
| | - Wanying Huang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, PR China
| | - Qianyi Xu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, PR China
| | - Jialing Zou
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, PR China
| | - Qiding Peng
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, PR China
| | - Honghui Lin
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, PR China
| | - Dehui Xi
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, PR China
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18
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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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19
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Kaushik P, Kumar P, Kumar S. Enhancement of chlorogenic content of the eggplant fruit with eggplant hydroxycinnamoyl CoA-quinate transferase gene via novel agroinfiltration protocol. Pharmacogn Mag 2020. [DOI: 10.4103/pm.pm_537_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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20
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Ehrnsberger HF, Grasser M, Grasser KD. Nucleocytosolic mRNA transport in plants: export factors and their influence on growth and development. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3757-3763. [PMID: 30972423 DOI: 10.1093/jxb/erz173] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/01/2019] [Indexed: 05/28/2023]
Abstract
In eukaryotes, the regulated transport of mRNAs from the cell nucleus to the cytosol is a critical step in the expression of protein-coding genes, as it links nuclear mRNA synthesis with cytosolic translation. The pre-mRNAs that are synthesised by RNA polymerase II are processed by 5´-capping, splicing, and 3´-polyadenylation. The multi-subunit THO/TREX complex integrates mRNA biogenesis with their nucleocytosolic transport. Various export factors are recruited to the mRNAs during their maturation, which occurs essentially co-transcriptionally. These RNA-bound export factors ensure efficient transport of the export-competent mRNAs through nuclear pore complexes. In recent years, several factors involved in plant mRNA export have been functionally characterised. Analysis of mutant plants has demonstrated that impaired mRNA export causes defects in growth and development. Moreover, there is accumulating evidence that mRNA export can influence processes such as plant immunity, circadian regulation, and stress responses. Therefore, it is important to learn more details about the mechanism of nucleocytosolic mRNA transport in plants and its physiological significance.
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Affiliation(s)
- Hans F Ehrnsberger
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, Regensburg, Germany
| | - Marion Grasser
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, Regensburg, Germany
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21
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Iki T, Cléry A, Bologna NG, Sarazin A, Brosnan CA, Pumplin N, Allain FHT, Voinnet O. Structural Flexibility Enables Alternative Maturation, ARGONAUTE Sorting and Activities of miR168, a Global Gene Silencing Regulator in Plants. MOLECULAR PLANT 2018; 11:1008-1023. [PMID: 29803952 DOI: 10.1016/j.molp.2018.05.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/26/2018] [Accepted: 05/15/2018] [Indexed: 06/08/2023]
Abstract
In eukaryotes, the RNase-III Dicer often produces length/sequence microRNA (miRNA) variants, called "isomiRs", owing to intrinsic structural/sequence determinants of the miRNA precursors (pre-miRNAs). In this study, we combined biophysics, genetics and biochemistry approaches to study Arabidopsis miR168, the key feedback regulator of central plant silencing effector protein ARGONAUTE1 (AGO1). We identified a motif conserved among plant pre-miR168 orthologs, which enables flexible internal base-pairing underlying at least three metastable structural configurations. These configurations promote alternative, accurate Dicer cleavage events generating length and structural isomiR168 variants with distinctive AGO sorting properties and modes of action. Among these isomiR168s, a duplex with a 22-nt guide strand exhibits strikingly preferential affinity for AGO10, the closest AGO1 paralog. The 22-nt miR168-AGO10 complex antagonizes AGO1 accumulation in part via "transitive RNAi", a silencing-amplification process, to maintain appropriate AGO1 cellular homeostasis. Furthermore, we found that the tombusviral P19 silencing-suppressor protein displays markedly weaker affinity for the 22-nt form among its isomiR168 cargoes, thereby promoting AGO10-directed suppression of AGO1-mediated antiviral silencing. Taken together, these findings indicate that structural flexibility, a previously overlooked property of pre-miRNAs, considerably increases the versatility and regulatory potential of individual MIRNA genes, and that some pathogens might have evolved the capacity or mechanisms to usurp this property.
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Affiliation(s)
- Taichiro Iki
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland.
| | - Antoine Cléry
- Institute of Molecular Biology and Biophysics, Department of Biology, Swiss Federal Institute of Technology (ETH), Zürich, Switzerland; Biomolecular NMR spectroscopy Platform, ETH Zürich, Switzerland
| | - Nicolas G Bologna
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Alexis Sarazin
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Christopher A Brosnan
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Nathan Pumplin
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Frédéric H T Allain
- Institute of Molecular Biology and Biophysics, Department of Biology, Swiss Federal Institute of Technology (ETH), Zürich, Switzerland
| | - Olivier Voinnet
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland.
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22
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Vinutha T, Kumar G, Garg V, Canto T, Palukaitis P, Ramesh SV, Praveen S. Tomato geminivirus encoded RNAi suppressor protein, AC4 interacts with host AGO4 and precludes viral DNA methylation. Gene 2018; 678:184-195. [PMID: 30081188 DOI: 10.1016/j.gene.2018.08.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 06/12/2018] [Accepted: 08/03/2018] [Indexed: 11/18/2022]
Abstract
Plant RNA silencing systems are organized as a network, regulating plant developmental pathways and restraining invading viruses, by sharing cellular components with overlapping functions. Host regulatory networks operate either at the transcriptional level via RNA-directed DNA methylation, or at the post-transcriptional stage interfering with mRNA to restrict viral infection. However, viral-derived proteins, including suppressors of RNA silencing, favour virus establishment, and also affect plant developmental processes. In this investigation, we report that Tomato leaf curl New Delhi virus-derived AC4 protein suppresses RNA silencing activity and mutational analysis of AC4 showed that Asn-50 in the SKNT-51 motif, in the C-terminal region, is a critical determinant of its RNA silencing suppressor activity. AC4 showed interaction with host AGO4 but not with AGO1, aggregated around the nucleus, and influenced cytosine methylation of the viral genome. The possible molecular mechanism by which AC4 interferes in the RNA silencing network, helps virus establishment, and affects plant development is discussed.
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Affiliation(s)
- T Vinutha
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi 110012, India
| | - Gaurav Kumar
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi 110012, India
| | - Varsha Garg
- Division of Plant Pathology, ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi 110012, India
| | - Tomas Canto
- Centro de Investigaciones Biológicas, CIB, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Peter Palukaitis
- Department of Horticultural Sciences, Seoul Women's University, Seoul 01797, Republic of Korea
| | - S V Ramesh
- ICAR-Central Plantation Crops Research Institute (ICAR-CPCRI), Kasaragod, Kerala 671 124, India.
| | - Shelly Praveen
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi 110012, India.
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23
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Osterbaan LJ, Schmitt-Keichinger C, Vigne E, Fuchs M. Optimal systemic grapevine fanleaf virus infection in Nicotiana benthamiana following agroinoculation. J Virol Methods 2018; 257:16-21. [PMID: 29630941 DOI: 10.1016/j.jviromet.2018.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 03/22/2018] [Accepted: 04/05/2018] [Indexed: 10/17/2022]
Abstract
One of the greatest hindrances to the study of grapevine fanleaf virus (GFLV) is the dearth of robust protocols for reliable, scalable, and cost-effective inoculation of host plants, especially methods which allow for rapid and targeted manipulation of the virus genome. Agroinoculation fulfills these requirements: it is a relatively rapid, inexpensive, and reliable method for establishing infections, and enables genetic manipulation of viral sequences by modifying plasmids. We designed a system of binary plasmids based on the two genomic RNAs [RNA1 (1) and RNA2 (2)] of GFLV strains F13 (F) and GHu (G) and optimized parameters to maximize systemic infection frequency in Nicotiana benthamiana via agroinoculation. The genomic make-up of the inoculum (G1-G2 and reassortant F1-G2), the identity of the co-infiltrated silencing suppressor (grapevine leafroll associated virus 2 p24), and temperature at which plants were maintained (25 °C) significantly increased systemic infection, while high optical densities of infiltration cultures (OD600nm of 1.0 or 2.0) increased the consistency of systemic infection frequency in N. benthamiana. In contrast, acetosyringone in the bacterial culture media, regardless of concentration, had no effect. Plasmids in this system are amenable to rapid and reliable manipulation by one-step site-directed mutagenesis, as shown by the creation of infectious RNA1 chimeras of the GFLV-F13 and GHu strains. The GFLV agroinoculation plasmids described here, together with the optimized protocol for bacterial culturing and plant maintenance, provide a robust system for the establishment of systemic GFLV infection in N. benthamiana and the rapid generation of GFLV mutants, granting a much-needed tool for investigations into GFLV-host interactions.
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Affiliation(s)
- Larissa J Osterbaan
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA.
| | - Corinne Schmitt-Keichinger
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, 12 Rue de Général Zimmer, 67084 Strasbourg, France
| | | | - Marc Fuchs
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA
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24
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Pfaff C, Ehrnsberger HF, Flores-Tornero M, Sørensen BB, Schubert T, Längst G, Griesenbeck J, Sprunck S, Grasser M, Grasser KD. ALY RNA-Binding Proteins Are Required for Nucleocytosolic mRNA Transport and Modulate Plant Growth and Development. PLANT PHYSIOLOGY 2018; 177:226-240. [PMID: 29540591 PMCID: PMC5933122 DOI: 10.1104/pp.18.00173] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 03/07/2018] [Indexed: 05/19/2023]
Abstract
The regulated transport of mRNAs from the cell nucleus to the cytosol is a critical step linking transcript synthesis and processing with translation. However, in plants, only a few of the factors that act in the mRNA export pathway have been functionally characterized. Flowering plant genomes encode several members of the ALY protein family, which function as mRNA export factors in other organisms. Arabidopsis (Arabidopsis thaliana) ALY1 to ALY4 are commonly detected in root and leaf cells, but they are differentially expressed in reproductive tissue. Moreover, the subnuclear distribution of ALY1/2 differs from that of ALY3/4. ALY1 binds with higher affinity to single-stranded RNA than double-stranded RNA and single-stranded DNA and interacts preferentially with 5-methylcytosine-modified single-stranded RNA. Compared with the full-length protein, the individual RNA recognition motif of ALY1 binds RNA only weakly. ALY proteins interact with the RNA helicase UAP56, indicating a link to the mRNA export machinery. Consistently, ALY1 complements the lethal phenotype of yeast cells lacking the ALY1 ortholog Yra1. Whereas individual aly mutants have a wild-type appearance, disruption of ALY1 to ALY4 in 4xaly plants causes vegetative and reproductive defects, including strongly reduced growth, altered flower morphology, as well as abnormal ovules and female gametophytes, causing reduced seed production. Moreover, polyadenylated mRNAs accumulate in the nuclei of 4xaly cells. Our results highlight the requirement of efficient mRNA nucleocytosolic transport for proper plant growth and development and indicate that ALY1 to ALY4 act partly redundantly in this process; however, differences in expression and subnuclear localization suggest distinct functions.
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Affiliation(s)
- Christina Pfaff
- Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - Hans F Ehrnsberger
- Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - María Flores-Tornero
- Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - Brian B Sørensen
- Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - Thomas Schubert
- Department for Biochemistry III, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - Gernot Längst
- Department for Biochemistry III, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - Joachim Griesenbeck
- Department for Biochemistry III, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - Stefanie Sprunck
- Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - Marion Grasser
- Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - Klaus D Grasser
- Department of Cell Biology and Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
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25
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Bologna NG, Iselin R, Abriata LA, Sarazin A, Pumplin N, Jay F, Grentzinger T, Dal Peraro M, Voinnet O. Nucleo-cytosolic Shuttling of ARGONAUTE1 Prompts a Revised Model of the Plant MicroRNA Pathway. Mol Cell 2018; 69:709-719.e5. [PMID: 29398448 DOI: 10.1016/j.molcel.2018.01.007] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 11/09/2017] [Accepted: 01/04/2018] [Indexed: 10/18/2022]
Abstract
Unlike in metazoans, plant microRNAs (miRNAs) undergo stepwise nuclear maturation before engaging cytosolic, sequence-complementary transcripts in association with the silencing effector protein ARGONAUTE1 (AGO1). Since their discovery, how and under which form plant miRNAs translocate to the cytosol has remained unclear, as has their sub-cellular AGO1 loading site(s). Here, we show that the N termini of all plant AGO1s contain a nuclear-localization (NLS) and nuclear-export signal (NES) that, in Arabidopsis thaliana (At), enables AtAGO1 nucleo-cytosolic shuttling in a Leptomycin-B-inhibited manner, diagnostic of CRM1(EXPO1)/NES-dependent nuclear export. Nuclear-only AtAGO1 contains the same 2'O-methylated miRNA cohorts as its nucleo-cytosolic counterpart, but it preferentially interacts with the miRNA loading chaperone HSP90. Furthermore, mature miRNA translocation and miRNA-mediated silencing both require AtAGO1 nucleo-cytosolic shuttling. These findings lead us to propose a substantially revised view of the plant miRNA pathway in which miRNAs are matured, methylated, loaded into AGO1 in the nucleus, and exported to the cytosol as AGO1:miRNA complexes in a CRM1(EXPO1)/NES-dependent manner.
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Affiliation(s)
- Nicolas G Bologna
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Raphael Iselin
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Luciano A Abriata
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland; Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland
| | - Alexis Sarazin
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Nathan Pumplin
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland; Department of Plant Sciences, University of California, Davis, California 95616, USA
| | - Florence Jay
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Thomas Grentzinger
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland; Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland
| | - Olivier Voinnet
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland.
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26
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Kalinina NO, Makarova S, Makhotenko A, Love AJ, Taliansky M. The Multiple Functions of the Nucleolus in Plant Development, Disease and Stress Responses. FRONTIERS IN PLANT SCIENCE 2018; 9:132. [PMID: 29479362 PMCID: PMC5811523 DOI: 10.3389/fpls.2018.00132] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/23/2018] [Indexed: 05/18/2023]
Abstract
The nucleolus is the most conspicuous domain in the eukaryotic cell nucleus, whose main function is ribosomal RNA (rRNA) synthesis and ribosome biogenesis. However, there is growing evidence that the nucleolus is also implicated in many other aspects of cell biology, such as regulation of cell cycle, growth and development, senescence, telomerase activity, gene silencing, responses to biotic and abiotic stresses. In the first part of the review, we briefly assess the traditional roles of the plant nucleolus in rRNA synthesis and ribosome biogenesis as well as possible functions in other RNA regulatory pathways such as splicing, nonsense-mediated mRNA decay and RNA silencing. In the second part of the review we summarize recent progress and discuss already known and new hypothetical roles of the nucleolus in plant growth and development. In addition, this part will highlight studies showing new nucleolar functions involved in responses to pathogen attack and abiotic stress. Cross-talk between the nucleolus and Cajal bodies is also discussed in the context of their association with poly(ADP ribose)polymerase (PARP), which is known to play a crucial role in various physiological processes including growth, development and responses to biotic and abiotic stresses.
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Affiliation(s)
- Natalia O. Kalinina
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russia
- Natalia O. Kalinina
| | - Svetlana Makarova
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russia
| | - Antonida Makhotenko
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russia
| | | | - Michael Taliansky
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russia
- The James Hutton Institute, Dundee, United Kingdom
- *Correspondence: Michael Taliansky
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27
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Chen L, Yan Z, Xia Z, Cheng Y, Jiao Z, Sun B, Zhou T, Fan Z. A Violaxanthin Deepoxidase Interacts with a Viral Suppressor of RNA Silencing to Inhibit Virus Amplification. PLANT PHYSIOLOGY 2017; 175:1774-1794. [PMID: 29021224 PMCID: PMC5717725 DOI: 10.1104/pp.17.00638] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 10/06/2017] [Indexed: 05/22/2023]
Abstract
RNA silencing plays a critical role against viral infection. To counteract this antiviral silencing, viruses have evolved various RNA silencing suppressors. Meanwhile, plants have evolved counter-counter defense strategies against RNA silencing suppression (RSS). In this study, the violaxanthin deepoxidase protein of maize (Zea mays), ZmVDE, was shown to interact specifically with the helper component-proteinase (HC-Pro; a viral RNA silencing suppressor) of Sugarcane mosaic virus (SCMV) via its mature protein region by yeast two-hybrid assay, which was confirmed by coimmunoprecipitation in Nicotiana benthamiana cells. It was demonstrated that amino acids 101 to 460 in HC-Pro and the amino acid glutamine-292 in ZmVDE mature protein were essential for this interaction. The mRNA levels of ZmVDE were down-regulated 75% to 65% at an early stage of SCMV infection. Interestingly, ZmVDE, which normally localized in the chloroplasts and cytoplasm, could relocalize to HC-Pro-containing aggregate bodies in the presence of HC-Pro alone or SCMV infection. In addition, ZmVDE could attenuate the RSS activity of HC-Pro in a specific protein interaction-dependent manner. Subsequently, transient silencing of the ZmVDE gene facilitated SCMV RNA and coat protein accumulation. Taken together, our results suggest that ZmVDE interacts with SCMV HC-Pro and attenuates its RSS activity, contributing to decreased SCMV accumulation. This study demonstrates that a host factor can be involved in secondary defense responses against viral infection in monocot plants.
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Affiliation(s)
- Ling Chen
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China
| | - Zhaoling Yan
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China
| | - Zihao Xia
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China
| | - Yuqin Cheng
- Department of Pomology/Laboratory of Stress Physiology and Molecular Biology for Tree Fruits-Key Laboratory of Beijing Municipality, China Agricultural University, Beijing 100193, China
| | - Zhiyuan Jiao
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China
| | - Biao Sun
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China
| | - Tao Zhou
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China
| | - Zaifeng Fan
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing 100193, China
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28
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Identification and functional characterization of three type III polyketide synthases from Aquilaria sinensis calli. Biochem Biophys Res Commun 2017; 486:1040-1047. [DOI: 10.1016/j.bbrc.2017.03.159] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 03/29/2017] [Indexed: 01/24/2023]
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29
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Widana Gamage SMK, Dietzgen RG. Intracellular Localization, Interactions and Functions of Capsicum Chlorosis Virus Proteins. Front Microbiol 2017; 8:612. [PMID: 28443083 PMCID: PMC5387057 DOI: 10.3389/fmicb.2017.00612] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/27/2017] [Indexed: 12/22/2022] Open
Abstract
Tospoviruses are among the most devastating viruses of horticultural and field crops. Capsicum chlorosis virus (CaCV) has emerged as an important pathogen of capsicum and tomato in Australia and South-east Asia. Present knowledge about CaCV protein functions in host cells is lacking. We determined intracellular localization and interactions of CaCV proteins by live plant cell imaging to gain insight into the associations of viral proteins during infection. Proteins were transiently expressed as fusions to autofluorescent proteins in leaf epidermal cells of Nicotiana benthamiana and capsicum. All viral proteins localized at least partially in the cell periphery suggestive of cytoplasmic replication and assembly of CaCV. Nucleocapsid (N) and non-structural movement (NSm) proteins localized exclusively in the cell periphery, while non-structural suppressor of silencing (NSs) protein and Gc and Gn glycoproteins accumulated in both the cell periphery and the nucleus. Nuclear localization of CaCV Gn and NSs is unique among tospoviruses. We validated nuclear localization of NSs by immunofluorescence in protoplasts. Bimolecular fluorescence complementation showed self-interactions of CaCV N, NSs and NSm, and heterotypic interactions of N with NSs and Gn. All interactions occurred in the cytoplasm, except NSs self-interaction was exclusively nuclear. Interactions of a tospoviral NSs protein with itself and with N had not been reported previously. Functionally, CaCV NSs showed strong local and systemic RNA silencing suppressor activity and appears to delay short-distance spread of silencing signal. Cell-to-cell movement activity of NSm was demonstrated by trans-complementation of a movement-defective tobamovirus replicon. CaCV NSm localized at plasmodesmata and its transient expression led to the formation of tubular structures that protruded from protoplasts. The D155 residue in the 30K-like movement protein-specific LxD/N50-70G motif of NSm was critical for plasmodesmata localization and movement activity. Compared to other tospoviruses, CaCV proteins have both conserved and unique properties in terms of in planta localization, interactions and protein functions which will effect viral multiplication and movement in host plants.
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Affiliation(s)
| | - Ralf G. Dietzgen
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St LuciaQLD, Australia
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30
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Wardhan V, Pandey A, Chakraborty S, Chakraborty N. Chickpea transcription factor CaTLP1 interacts with protein kinases, modulates ROS accumulation and promotes ABA-mediated stomatal closure. Sci Rep 2016; 6:38121. [PMID: 27934866 PMCID: PMC5146945 DOI: 10.1038/srep38121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 11/07/2016] [Indexed: 11/23/2022] Open
Abstract
Tubby and Tubby-like proteins (TLPs), in mammals, play critical roles in neural development, while its function in plants is largely unknown. We previously demonstrated that the chickpea TLP, CaTLP1, participates in osmotic stress response and might be associated with ABA-dependent network. However, how CaTLP1 is connected to ABA signaling remains unclear. The CaTLP1 was found to be engaged in ABA-mediated gene expression and stomatal closure. Complementation of the yeast yap1 mutant with CaTLP1 revealed its role in ROS scavenging. Furthermore, complementation of Arabidopsis attlp2 mutant displayed enhanced stress tolerance, indicating the functional conservation of TLPs across the species. The presence of ABA-responsive element along with other motifs in the proximal promoter regions of TLPs firmly established their involvement in stress signalling pathways. The CaTLP1 promoter driven GUS expression was restricted to the vegetative organs, especially stem and rosette leaves. Global protein expression profiling of wild-type, attlp2 and complemented Arabidopsis plants revealed 95 differentially expressed proteins, presumably involved in maintaining physiological and biological processes under dehydration. Immunoprecipitation assay revealed that protein kinases are most likely to interact with CaTLP1. This study provides the first demonstration that the TLPs act as module for ABA-mediated stomatal closure possibly via interaction with protein kinase.
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Affiliation(s)
- Vijay Wardhan
- National Institute of Plant Genome Research, Jawaharlal Nehru University Campus, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Aarti Pandey
- National Institute of Plant Genome Research, Jawaharlal Nehru University Campus, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Subhra Chakraborty
- National Institute of Plant Genome Research, Jawaharlal Nehru University Campus, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Niranjan Chakraborty
- National Institute of Plant Genome Research, Jawaharlal Nehru University Campus, Aruna Asaf Ali Marg, New Delhi-110067, India
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31
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Miyashita Y, Atsumi G, Nakahara KS. Trade-Offs for Viruses in Overcoming Innate Immunities in Plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:595-8. [PMID: 27294885 DOI: 10.1094/mpmi-05-16-0103-cr] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Plants recognize viral infection via an immune receptor, i.e., nucleotide-binding site (NB)-leucine-rich repeat (LRR) proteins. Another immune receptor, receptor-like kinase proteins, which share an LRR domain with NB-LRRs, perceive conserved molecules of pathogens called pathogen- or microbe-associated molecular patterns, but NB-LRRs generally perceive particular viral proteins. As viruses can evolve more rapidly than the host immune system, how do plant immune systems, which rely on the perception of proteins, remain effective? Viral adaptive evolution may be controlled by penalties that result from mutations in viral proteins that are perceived by NB-LRRs. Our recent studies in pea (Pisum sativum) suggest a penalty of increased susceptibility to another immune system. When a viral protein mutates to evade one immune system, the virus with the mutated protein becomes more susceptible to another. Such antagonistic pleiotropy of a viral protein by two independent plant immune systems may have precedents. Plants may rely on pairs of immune systems to constrain adaptive evolution by viruses and thereby maintain durable antiviral immunity.
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Affiliation(s)
- Yuri Miyashita
- 1 Pathogen-Plant Interactions Group, Plant Breeding Science, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan; and
| | - Go Atsumi
- 2 National Institute of Advanced Industrial Science and Technology, Sapporo 062-8517, Japan
| | - Kenji S Nakahara
- 1 Pathogen-Plant Interactions Group, Plant Breeding Science, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan; and
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32
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Miyashita Y, Atsumi G, Nakahara KS. Trade-Offs for Viruses in Overcoming Innate Immunities in Plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 2016:1-4. [PMID: 27838953 DOI: 10.1094/mpmi-05-16-0103-cr.2016.1.test] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Plants recognize viral infection via an immune receptor, i.e., nucleotide-binding site (NB)-leucine-rich repeat (LRR) proteins. Another immune receptor, receptor-like kinase proteins, which share an LRR domain with NB-LRRs, perceive conserved molecules of pathogens called pathogen- or microbe-associated molecular patterns, but NB-LRRs generally perceive particular viral proteins. As viruses can evolve more rapidly than the host immune system, how do plant immune systems, which rely on the perception of proteins, remain effective? Viral adaptive evolution may be controlled by penalties that result from mutations in viral proteins that are perceived by NB-LRRs. Our recent studies in pea (Pisum sativum) suggest a penalty of increased susceptibility to another immune system. When a viral protein mutates to evade one immune system, the virus with the mutated protein becomes more susceptible to another. Such antagonistic pleiotropy of a viral protein by two independent plant immune systems may have precedents. Plants may rely on pairs of immune systems to constrain adaptive evolution by viruses and thereby maintain durable antiviral immunity. [Formula: see text] Copyright © 2016 The Author(s). This is an open access article distributed under the CC BY-NC 4.0 International license .
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Affiliation(s)
- Yuri Miyashita
- 1 Pathogen-Plant Interactions Group, Plant Breeding Science, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan; and
| | - Go Atsumi
- 2 National Institute of Advanced Industrial Science and Technology, Sapporo 062-8517, Japan
| | - Kenji S Nakahara
- 1 Pathogen-Plant Interactions Group, Plant Breeding Science, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan; and
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33
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Dong OX, Meteignier LV, Plourde MB, Ahmed B, Wang M, Jensen C, Jin H, Moffett P, Li X, Germain H. Arabidopsis TAF15b Localizes to RNA Processing Bodies and Contributes to snc1-Mediated Autoimmunity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:247-57. [PMID: 26713351 DOI: 10.1094/mpmi-11-15-0246-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In both animals and plants, messenger (m)RNA export has been shown to contribute to immune response regulation. The Arabidopsis nuclear protein MOS11, along with the nucleoporins MOS3/Nup96/SAR3 and Nup160/SAR1 are components of the mRNA export machinery and contribute to immunity mediated by nucleotide binding leucine-rich repeat immune receptors (NLR). The human MOS11 ortholog CIP29 is part of a small protein complex with three additional members: the RNA helicase DDX39, ALY, and TAF15b. We systematically assessed the biological roles of the Arabidopsis homologs of these proteins in toll interleukin 1 receptor-type NLR (TNL)-mediated immunity using reverse genetics. Although mutations in ALY and DDX39 did not result in obvious defects, taf15b mutation partially suppressed the autoimmune phenotypes of a gain-of-function TNL mutant, snc1. An additive effect on snc1 suppression was observed in mos11-1 taf15b snc1 triple mutant plants, suggesting that MOS11 and TAF15b have independent functions. TAF15b-GFP fusion protein, which fully complemented taf15b mutant phenotypes, localized to nuclei similarly to MOS11. However, it was also targeted to cytosolic granules identified as processing bodies. In addition, we observed no change in SNC1 mRNA levels, whereas less SNC1 protein accumulated in taf15b mutant, suggesting that TAF15b contributes to SNC1 homeostasis through posttranscriptional mechanisms. In summary, this study highlights the importance of posttranscriptional RNA processing mediated by TAF15b in the regulation of TNL-mediated immunity.
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Affiliation(s)
- Oliver X Dong
- 1 Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- 2 Michael Smith Laboratories, University of British Columbia
| | | | - Melodie B Plourde
- 4 Department of Chemistry, Biochemistry and Physics, Université du Québec à Trois-Rivières, QC, G9A 5H7, Canada
- 5 Groupe de Recherche en Biologie Végétale (GRBV), Université du Québec à Trois-Rivières; and
| | - Bulbul Ahmed
- 4 Department of Chemistry, Biochemistry and Physics, Université du Québec à Trois-Rivières, QC, G9A 5H7, Canada
- 5 Groupe de Recherche en Biologie Végétale (GRBV), Université du Québec à Trois-Rivières; and
| | - Ming Wang
- 6 Department of Plant Pathology and Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, U.S.A
| | | | - Hailing Jin
- 6 Department of Plant Pathology and Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, U.S.A
| | - Peter Moffett
- 3 Department of Biology, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Xin Li
- 1 Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- 2 Michael Smith Laboratories, University of British Columbia
| | - Hugo Germain
- 4 Department of Chemistry, Biochemistry and Physics, Université du Québec à Trois-Rivières, QC, G9A 5H7, Canada
- 5 Groupe de Recherche en Biologie Végétale (GRBV), Université du Québec à Trois-Rivières; and
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34
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Fernández-Calvino L, Martínez-Priego L, Szabo EZ, Guzmán-Benito I, González I, Canto T, Lakatos L, Llave C. Tobacco rattle virus 16K silencing suppressor binds ARGONAUTE 4 and inhibits formation of RNA silencing complexes. J Gen Virol 2016; 97:246-257. [PMID: 26498945 DOI: 10.1099/jgv.0.000323] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The cysteine-rich 16K protein of tobacco rattle virus (TRV), the type member of the genus Tobravirus, is known to suppress RNA silencing. However, the mechanism of action of the 16K suppressor is not well understood. In this study, we used a GFP-based sensor strategy and an Agrobacterium-mediated transient assay in Nicotiana benthamiana to show that 16K was unable to inhibit the activity of existing small interfering RNA (siRNA)- and microRNA (miRNA)-programmed RNA-induced silencing effector complexes (RISCs). In contrast, 16K efficiently interfered with de novo formation of miRNA- and siRNA-guided RISCs, thus preventing cleavage of target RNA. Interestingly, we found that transiently expressed endogenous miR399 and miR172 directed sequence-specific silencing of complementary sequences of viral origin. 16K failed to bind small RNAs, although it interacted with ARGONAUTE 4, as revealed by bimolecular fluorescence complementation and immunoprecipitation assays. Site-directed mutagenesis demonstrated that highly conserved cysteine residues within the N-terminal and central regions of the 16K protein are required for protein stability and/or RNA silencing suppression.
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Affiliation(s)
- Lourdes Fernández-Calvino
- Department of Environmental Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Llúcia Martínez-Priego
- Department of Environmental Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Edit Z Szabo
- Department of Dermatology and Allergology, University of Szeged, H-6720 Szeged, Koranyi str. 6, Hungary
| | - Irene Guzmán-Benito
- Department of Environmental Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Inmaculada González
- Department of Environmental Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Tomás Canto
- Department of Environmental Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Lóránt Lakatos
- Department of Dermatology and Allergology, University of Szeged, H-6720 Szeged, Koranyi str. 6, Hungary
- MTA-SZTE Dermatological Research Group, Hungary
| | - César Llave
- Department of Environmental Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
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Del Toro F, Tenllado F, Chung BN, Canto T. A procedure for the transient expression of genes by agroinfiltration above the permissive threshold to study temperature-sensitive processes in plant-pathogen interactions. MOLECULAR PLANT PATHOLOGY 2014; 15:848-57. [PMID: 24581046 PMCID: PMC6638763 DOI: 10.1111/mpp.12136] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Localized expression of genes in plants from T-DNAs delivered into plant cells by Agrobacterium tumefaciens is an important tool in plant research. The technique, known as agroinfiltration, provides fast, efficient ways to transiently express or silence a desired gene without resorting to the time-consuming, challenging stable transformation of the host, the use of less efficient means of delivery, such as bombardment, or the use of viral vectors, which multiply and spread within the host causing physiological alterations themselves. A drawback of the agroinfiltration technique is its temperature dependence: early studies have shown that temperatures above 29 °C are nonpermissive to tumour induction by the bacterium as a result of failure in pilus formation. However, research in plant sciences is interested in studying processes at these temperatures, above the 25 °C experimental standard, common to many host-environment and host-pathogen interactions in nature, and agroinfiltration is an excellent tool for this purpose. Here, we measured the efficiency of agroinfiltration for the expression of reporter genes in plants from T-DNAs at the nonpermissive temperature of 30 °C, either transiently or as part of viral amplicons, and envisaged procedures that allow and optimize its use for gene expression at this temperature. We applied this technical advance to assess the performance at 30 °C of two viral suppressors of silencing in agropatch assays [Potato virus Y helper component proteinase (HCPro) and Cucumber mosaic virus 2b protein] and, within the context of infection by a Potato virus X (PVX) vector, also assessed indirectly their effect on the overall response of the host Nicotiana benthamiana to the virus.
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Affiliation(s)
- Francisco Del Toro
- Environmental Biology Department, Centro de Investigaciones Biológicas, CIB-CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
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Teng W, Zhang H, Wang W, Li D, Wang M, Liu J, Zhang H, Zheng X, Zhang Z. ALY proteins participate in multifaceted Nep1Mo-triggered responses in Nicotiana benthamiana and Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2483-94. [PMID: 24723400 PMCID: PMC4036512 DOI: 10.1093/jxb/eru136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Previously, it was found that Nep1Mo (a Nep1-like protein from Magnaporthe oryzae) could trigger a variety of plant responses, including stomatal closure, hypersensitive cell death (HCD), and defence-related gene expression, in Nicotiana benthamiana. In this study, it was found that Nep1Mo-induced cell death could be inhibited by the virus-induced gene silencing of NbALY916 in N. benthamiana. NbALY916-silenced plants showed impaired Nep1Mo-induced stomatal closure, decreased Nep1Mo-induced production of hydrogen peroxide (H2O2) and nitric oxide (NO) in guard cells, and reduced Nep1Mo-induced resistance against Phytophthora nicotianae. It also found that the deletion of AtALY4, an orthologue of NbALY916 in Arabidopsis thaliana, impaired Nep1Mo-triggered stomatal closure, HCD, and defence-related gene expression. The compromised stomatal closure observed in the NbALY916-silenced plants and AtALY4 mutants was inhibited by the application of H2O2 and sodium nitroprusside (an NO donor), and both Nep1Mo and H2O2 stimulated guard cell NO synthesis. Conversely, NO-induced stomatal closure was found not to require H2O2 synthesis; and NO treatment did not induce H2O2 production in guard cells. Taken together, these results demonstrate that the NbAlY916/AtAlY4-H2O2-NO pathway mediates multiple Nep1Mo-triggered responses, including stomatal closure, HCD, and defence-related gene expression.
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Affiliation(s)
- Wenjun Teng
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Huajian Zhang
- Department of Plant Pathology, College of Plant Protection, Anhui Agricultural University, Hefei, 230036, China
| | - Wei Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Deqing Li
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Meifang Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Jiewen Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Haifeng Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Xiaobo Zheng
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Zhengguang Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
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Sahana N, Kaur H, Jain RK, Palukaitis P, Canto T, Praveen S. The asparagine residue in the FRNK box of potyviral helper-component protease is critical for its small RNA binding and subcellular localization. J Gen Virol 2014; 95:1167-1177. [PMID: 24526574 DOI: 10.1099/vir.0.060269-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The multifunctional potyviral helper-component protease (HcPro) contains variable regions with some functionally conserved domains, such as the FRNK box. Natural variants occur at the FRNK box, a conserved central domain, known for its role in RNA binding and RNAi suppression activities, although no dominant natural variants for the N(182) residue are known to occur. Here, a mutant at HcPro(N182L) was developed to investigate its role in natural populations. Using in vitro studies, we found an increase in the small RNA (sRNA) binding potential of HcPro(N182L) without affecting its protein-protein interaction properties, suggesting that the presence of N(182) is critical to maintain threshold levels of sRNAs, but does not interfere in the self-interaction of HcPro. Furthermore, we found that expression of HcPro(N182L) in Nicotiana benthamiana affected plant growth. Transient expression of HcPro(N182L) induced reporter gene expression in 16c GFP transgenic plants more than HcPro did, suggesting that replacement of asparagine in the FRNK box favours RNA silencing suppression. HcPro was found to be distributed in the nucleus and cytoplasm, whereas HcPro(N182L) was observed only in cytoplasmic inclusion bodies in N. benthamiana leaves, when fused to a GFP tag and expressed by agro-infiltration, suggesting mutation favours oligomerization of HcPro. These findings suggest that amino acid N(182) of the conserved FRNK box may regulate RNA silencing mechanisms, and is required for maintenance of the subcellular localization of the protein for its multi-functionality. Hence, the N(182) residue of the FRNK box seems to be indispensable for potyvirus infection during evolution.
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Affiliation(s)
- Nandita Sahana
- Division of Biochemistry, Indian Agricultural Research Institute, New Delhi 110012, India
| | - Harpreet Kaur
- Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi 110012, India
| | - R K Jain
- Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi 110012, India
| | - Peter Palukaitis
- Department of Horticultural Science, Seoul Women's University, Seoul 139-774, Republic of Korea
| | - Tomas Canto
- Centro de Investigaciones Biológicas, CIB, CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
| | - Shelly Praveen
- Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi 110012, India
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Nuclear-cytoplasmic partitioning of cucumber mosaic virus protein 2b determines the balance between its roles as a virulence determinant and an RNA-silencing suppressor. J Virol 2014; 88:5228-41. [PMID: 24599997 PMCID: PMC4019134 DOI: 10.1128/jvi.00284-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The Cucumber Mosaic Virus (CMV) 2b protein is an RNA-silencing suppressor that plays roles in CMV accumulation and virulence. The 2b proteins of subgroup IA CMV strains partition between the nucleus and cytoplasm, but the biological significance of this is uncertain. We fused an additional nuclear localization signal (NLS) to the 2b protein of subgroup IA strain Fny-CMV to create 2b-NLS and tested its effects on subcellular distribution, silencing, and virulence. The additional NLS enhanced 2b protein nuclear and nucleolar accumulation, but nuclear and nucleolar enrichment correlated with markedly diminished silencing suppressor activity in patch assays and abolished 2b protein-mediated disruption of microRNA activity in transgenic Arabidopsis. Nucleus/nucleolus-localized 2b protein possesses at least some ability to inhibit antiviral silencing, but this was not sufficient to prevent recovery from disease in younger, developing leaves in Arabidopsis. However, enhanced nuclear and nucleolar accumulation of 2b increased virulence and accelerated symptom appearance in older leaves. Experiments with Arabidopsis lines carrying mutant Dicer-like alleles demonstrated that compromised suppressor activity explained the diminished ability of 2b-NLS to enhance virus accumulation. Remarkably, the increased virulence that 2b-NLS engendered was unrelated to effects on microRNA- or short interfering RNA-regulated host functions. Thus, although nucleus- and nucleolus-localized 2b protein is less efficient at silencing suppression than cytoplasm-localized 2b, it enhances CMV virulence. We propose that partitioning of the 2b protein between the cytoplasmic and nuclear/nucleolar compartments allows CMV to regulate the balance between virus accumulation and damage to the host, presumably to maximize the benefit for the virus. IMPORTANCE In this work, the main finding is that nucleus/nucleolus-localized 2b protein is strongly associated with CMV virulence, which is independent of its effect on small RNA pathways. Moreover, this work supports the contention that the silencing suppressor activity of CMV 2b protein is predominantly exerted by that portion of the 2b protein residing in the cytoplasm. Thus, we propose that partitioning of the 2b protein between the cytoplasmic and nuclear/nucleolar compartments allows CMV to regulate the balance between virus accumulation and damage to the host, presumably to maximize the benefit for the virus.
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Fan H, Sun H, Wang Y, Zhang Y, Wang X, Li D, Yu J, Han C. Deep sequencing-based transcriptome profiling reveals comprehensive insights into the responses of Nicotiana benthamiana to beet necrotic yellow vein virus infections containing or lacking RNA4. PLoS One 2014; 9:e85284. [PMID: 24416380 PMCID: PMC3887015 DOI: 10.1371/journal.pone.0085284] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 11/26/2013] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Beet necrotic yellow vein virus (BNYVV), encodes either four or five plus-sense single stranded RNAs and is the causal agent of sugar beet rhizomania disease, which is widely distributed in most regions of the world. BNYVV can also infect Nicotiana benthamiana systemically, and causes severe curling and stunting symptoms in the presence of RNA4 or mild symptoms in the absence of RNA4. RESULTS Confocal laser scanning microscopy (CLSM) analyses showed that the RNA4-encoded p31 protein fused to the red fluorescent protein (RFP) accumulated mainly in the nuclei of N. benthamiana epidermal cells. This suggested that severe RNA4-induced symptoms might result from p31-dependent modifications of the transcriptome. Therefore, we used next-generation sequencing technologies to analyze the transcriptome profile of N. benthamiana in response to infection with different isolates of BNYVV. Comparisons of the transcriptomes of mock, BN3 (RNAs 1+2+3), and BN34 (RNAs 1+2+3+4) infected plants identified 3,016 differentially expressed transcripts, which provided a list of candidate genes that potentially are elicited in response to virus infection. Our data indicate that modifications in the expression of genes involved in RNA silencing, ubiquitin-proteasome pathway, cellulose synthesis, and metabolism of the plant hormone gibberellin may contribute to the severe symptoms induced by RNA4 from BNYVV. CONCLUSIONS These results expand our understanding of the genetic architecture of N. benthamiana as well as provide valuable clues to identify genes potentially involved in resistance to BNYVV infection. Our global survey of gene expression changes in infected plants reveals new insights into the complicated molecular mechanisms underlying symptom development, and aids research into new strategies to protect crops against viruses.
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Affiliation(s)
- Huiyan Fan
- State Key Laboratory for Agrobiotechnology and Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Haiwen Sun
- State Key Laboratory for Agrobiotechnology and Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Ying Wang
- State Key Laboratory for Agrobiotechnology and Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Yongliang Zhang
- State Key Laboratory for Agrobiotechnology and Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Xianbing Wang
- State Key Laboratory for Agrobiotechnology and Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Dawei Li
- State Key Laboratory for Agrobiotechnology and Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Jialin Yu
- State Key Laboratory for Agrobiotechnology and Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Chenggui Han
- State Key Laboratory for Agrobiotechnology and Department of Plant Pathology, China Agricultural University, Beijing, China
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Westwood JH, Groen SC, Du Z, Murphy AM, Anggoro DT, Tungadi T, Luang-In V, Lewsey MG, Rossiter JT, Powell G, Smith AG, Carr JP. A trio of viral proteins tunes aphid-plant interactions in Arabidopsis thaliana. PLoS One 2013; 8:e83066. [PMID: 24349433 PMCID: PMC3859657 DOI: 10.1371/journal.pone.0083066] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 11/07/2013] [Indexed: 12/23/2022] Open
Abstract
Background Virus-induced deterrence to aphid feeding is believed to promote plant virus transmission by encouraging migration of virus-bearing insects away from infected plants. We investigated the effects of infection by an aphid-transmitted virus, cucumber mosaic virus (CMV), on the interaction of Arabidopsis thaliana, one of the natural hosts for CMV, with Myzus persicae (common names: ‘peach-potato aphid’, ‘green peach aphid’). Methodology/Principal Findings Infection of Arabidopsis (ecotype Col-0) with CMV strain Fny (Fny-CMV) induced biosynthesis of the aphid feeding-deterrent 4-methoxy-indol-3-yl-methylglucosinolate (4MI3M). 4MI3M inhibited phloem ingestion by aphids and consequently discouraged aphid settling. The CMV 2b protein is a suppressor of antiviral RNA silencing, which has previously been implicated in altering plant-aphid interactions. Its presence in infected hosts enhances the accumulation of CMV and the other four viral proteins. Another viral gene product, the 2a protein (an RNA-dependent RNA polymerase), triggers defensive signaling, leading to increased 4MI3M accumulation. The 2b protein can inhibit ARGONAUTE1 (AGO1), a host factor that both positively-regulates 4MI3M biosynthesis and negatively-regulates accumulation of substance(s) toxic to aphids. However, the 1a replicase protein moderated 2b-mediated inhibition of AGO1, ensuring that aphids were deterred from feeding but not poisoned. The LS strain of CMV did not induce feeding deterrence in Arabidopsis ecotype Col-0. Conclusions/Significance Inhibition of AGO1 by the 2b protein could act as a booby trap since this will trigger antibiosis against aphids. However, for Fny-CMV the interplay of three viral proteins (1a, 2a and 2b) appears to balance the need of the virus to inhibit antiviral silencing, while inducing a mild resistance (antixenosis) that is thought to promote transmission. The strain-specific effects of CMV on Arabidopsis-aphid interactions, and differences between the effects of Fny-CMV on this plant and those seen previously in tobacco (inhibition of resistance to aphids) may have important epidemiological consequences.
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Affiliation(s)
- Jack H Westwood
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Simon C Groen
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Zhiyou Du
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Alex M Murphy
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Damar Tri Anggoro
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Trisna Tungadi
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | | | - Mathew G Lewsey
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | | | | | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - John P Carr
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
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Tena Fernández F, González I, Doblas P, Rodríguez C, Sahana N, Kaur H, Tenllado F, Praveen S, Canto T. The influence of cis-acting P1 protein and translational elements on the expression of Potato virus Y helper-component proteinase (HCPro) in heterologous systems and its suppression of silencing activity. MOLECULAR PLANT PATHOLOGY 2013; 14:530-41. [PMID: 23451733 PMCID: PMC6638740 DOI: 10.1111/mpp.12025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In the Potyvirus genus, the P1 protein is the first N-terminal product processed from the viral polyprotein, followed by the helper-component proteinase (HCPro). In silencing suppression patch assays, we found that Potato virus Y (PVY) HCPro expressed from a P1-HCPro sequence increased the accumulation of a reporter gene, whereas protein expressed from an HCPro sequence did not, even with P1 supplied in trans. This enhancing effect of P1 has been noted in other potyviruses, but has remained unexplained. We analysed the accumulation of PVY HCPro in infiltrated tissues and found that it was higher when expressed from P1-HCPro than from HCPro sequences. Co-expression of heterologous suppressors increased the steady-state level of mRNA expressed from the HCPro sequence, but not that of protein. This suggests that, in the absence of P1 upstream, either HCPro acquires a conformation that affects negatively its activity or stability, or that its translation is reduced. To test these options, we purified HCPro expressed in the presence or absence of upstream P1, and found no difference in purification pattern and final soluble state. By contrast, alteration of the Kozak context in the HCPro mRNA sequence to favour translation increased partially suppressor accumulation and activity. Furthermore, protein activity was not lower than in protein expressed from P1-HCPro sequences. Thus, a direct role for P1 on HCPro suppressor activity or stability, by influencing its conformation during translation, can be excluded. However, P1 could still have an indirect effect favouring HCPro accumulation. Our data highlight the relevance of cis-acting translational elements in the heterologous expression of HCPro.
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Affiliation(s)
- Fátima Tena Fernández
- Environmental Biology Department, Centro de Investigaciones Biológicas, CIB-CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
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Gaouar O, Germain H. mRNA export: threading the needle. FRONTIERS IN PLANT SCIENCE 2013; 4:59. [PMID: 23526740 PMCID: PMC3605508 DOI: 10.3389/fpls.2013.00059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 03/04/2013] [Indexed: 05/29/2023]
Abstract
After mRNA biogenesis, several proteins interact with the messenger to ensure its proper export to the cytoplasm. Some of these proteins will bind RNA early on, at the onset of transcription by RNA polymerase II holoenzyme, while others will join later for downstream processing steps, such as poly-adenylation or splicing, or may direct mRNA ribonucleoprotein particle migration to the nucleopore. We recently discovered that Arabidopsis plant knockout for the protein MOS11 (MODIFIER OF SNC1, 11) partially suppresses autoimmune responses observed in the TNL-type [TIR/NBS/LRR (Toll-interleukin-like receptor/nucleotide-binding site/C-terminal leucine-rich repeat)] R gene gain-of-function variant snc1 (suppressor of npr1-1, constitutive 1). This suppression of resistance to pathogens appears to be caused by a decrease in nuclear mRNA export in mos11-1 snc1 plants. In humans, the putative ortholog of MOS11, CIP29 (29-kDa cytokine-induced protein), interacts with three proteins that are also involved in mRNA export: DDX39 (DEAD-box RNA helicase), TAF15 of the FUS family (FUSED IN SARCOMA), and ALY (ALWAYS EARLY), a protein implicated in mRNA export in mammalian systems. These proteins have received very little attention in plants. Here, we will discuss their particularities and role in mRNA export and biotic stress.
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Affiliation(s)
| | - Hugo Germain
- *Correspondence: Hugo Germain, Groupe de Recherche en Biologie Végétale, Département de Chimie et Physique, Université du Québec à Trois-Rivières, 3351, Boulevard des Forges, Trois-Rivières, QC, Canada G9A 5H7. e-mail:
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Danielson DC, Pezacki JP. Studying the RNA silencing pathway with the p19 protein. FEBS Lett 2013; 587:1198-205. [PMID: 23376479 DOI: 10.1016/j.febslet.2013.01.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/17/2013] [Accepted: 01/18/2013] [Indexed: 01/05/2023]
Abstract
The origins of the RNA silencing pathway are in defense against invading viruses and in response, viruses have evolved counter-measures to interfere with the host pathway. The p19 protein is expressed by tombusviruses as a suppressor of RNA silencing and functions to sequester small RNA duplexes, thereby preventing induction of the pathway. p19 exhibits size-specific and sequence-independent binding of its small RNA ligands, binding with high affinity to duplexes 20-22 nucleotides long. p19's binding specificity and its ability to sequester small RNAs has made it a unique protein-based tool for probing the molecular mechanisms of the highly complex RNA silencing pathway in a variety of systems. Furthermore, protein engineering of this 'molecular caliper' promises novel applications in biotechnology and medicine where small RNA molecules are of remarkable interest given their potent gene regulatory abilities.
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Affiliation(s)
- Dana C Danielson
- Department of Biochemistry, Microbiology & Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Canada K1H 8M5
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Sahana N, Kaur H, Basavaraj, Tena F, Jain RK, Palukaitis P, Canto T, Praveen S. Inhibition of the host proteasome facilitates papaya ringspot virus accumulation and proteosomal catalytic activity is modulated by viral factor HcPro. PLoS One 2012; 7:e52546. [PMID: 23300704 PMCID: PMC3531422 DOI: 10.1371/journal.pone.0052546] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Accepted: 11/19/2012] [Indexed: 11/19/2022] Open
Abstract
The ubiquitin/26S proteasome system plays an essential role not only in maintaining protein turnover, but also in regulating many other plant responses, including plant-pathogen interactions. Previous studies highlighted different roles of the 20S proteasome in plant defense during virus infection, either indirectly through viral suppressor-mediated degradation of Argonaute proteins, affecting the RNA interference pathway, or directly through modulation of the proteolytic and RNase activity of the 20S proteasome, a component of the 20S proteasome, by viral proteins, affecting the levels of viral proteins and RNAs. Here we show that MG132, a cell permeable proteasomal inhibitor, caused an increase in papaya ringspot virus (PRSV) accumulation in its natural host papaya (Carica papaya). We also show that the PRSV HcPro interacts with the papaya homologue of the Arabidopsis PAA (α1 subunit of the 20S proteasome), but not with the papaya homologue of Arabidopsis PAE (α5 subunit of the 20S proteasome), associated with the RNase activity, although the two 20S proteasome subunits interacted with each other. Mutated forms of PRSV HcPro showed that the conserved KITC54 motif in the N-terminal domain of HcPro was necessary for its binding to PAA. Co-agroinfiltration assays demonstrated that HcPro expression mimicked the action of MG132, and facilitated the accumulation of bothtotal ubiquitinated proteins and viral/non-viral exogenous RNA in Nicotiana benthamiana leaves. These effects were not observed by using an HcPro mutant (KITS54), which impaired the HcPro - PAA interaction. Thus, the PRSV HcPro interacts with a proteasomal subunit, inhibiting the action of the 20S proteasome, suggesting that HcPro might be crucial for modulating its catalytic activities in support of virus accumulation.
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Affiliation(s)
- Nandita Sahana
- Division of Biochemistry, Indian Agricultural Research Institute, New Delhi, India
| | - Harpreet Kaur
- Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Basavaraj
- Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Fatima Tena
- Centro de Investigaciones Biológicas, CIB, CSIC, Madrid, Spain
| | - Rakesh Kumar Jain
- Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Peter Palukaitis
- Department of Horticultural Science, Seoul Women’s University, Seoul, South Korea
| | - Tomas Canto
- Centro de Investigaciones Biológicas, CIB, CSIC, Madrid, Spain
| | - Shelly Praveen
- Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
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Herranz MC, Pallas V, Aparicio F. Multifunctional roles for the N-terminal basic motif of Alfalfa mosaic virus coat protein: nucleolar/cytoplasmic shuttling, modulation of RNA-binding activity, and virion formation. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:1093-103. [PMID: 22746826 DOI: 10.1094/mpmi-04-12-0079-r] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
In addition to virion formation, the coat protein (CP) of Alfalfa mosaic virus (AMV) is involved in the regulation of replication and translation of viral RNAs, and in cell-to-cell and systemic movement of the virus. An intriguing feature of the AMV CP is its nuclear and nucleolar accumulation. Here, we identify an N-terminal lysine-rich nucleolar localization signal (NoLS) in the AMV CP required to both enter the nucleus and accumulate in the nucleolus of infected cells, and a C-terminal leucine-rich domain which might function as a nuclear export signal. Moreover, we demonstrate that AMV CP interacts with importin-α, a component of the classical nuclear import pathway. A mutant AMV RNA 3 unable to target the nucleolus exhibited reduced plus-strand RNA synthesis and cell-to-cell spread. Moreover, virion formation and systemic movement were completely abolished in plants infected with this mutant. In vitro analysis demonstrated that specific lysine residues within the NoLS are also involved in modulating CP-RNA binding and CP dimerization, suggesting that the NoLS represents a multifunctional domain within the AMV CP. The observation that nuclear and nucleolar import signals mask RNA-binding properties of AMV CP, essential for viral replication and translation, supports a model in which viral expression is carefully modulated by a cytoplasmic/nuclear balance of CP accumulation.
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Affiliation(s)
- Mari Carmen Herranz
- Department of Molecular and Evolutionary Plant Virology, Instituto de Biologia Molecular y Celular de Plantas, Valencia, Spain
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Wang X, Zhang Y, Xu J, Shi L, Fan H, Han C, Li D, Yu J. The R-rich motif of Beet black scorch virus P7a movement protein is important for the nuclear localization, nucleolar targeting and viral infectivity. Virus Res 2012; 167:207-18. [PMID: 22626884 PMCID: PMC7172424 DOI: 10.1016/j.virusres.2012.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Revised: 05/01/2012] [Accepted: 05/06/2012] [Indexed: 01/07/2023]
Abstract
Beet black scorch virus (BBSV) encodes three movement proteins (P7a, P7b and P5') that facilitate its cell-to-cell movement. An arginine-rich motif of P7a N-terminus was found to determine nuclear and nucleolar localization. Amino acids substitution or deletion of the R-rich motif interfered with P7a nuclear and nucleolar localization. Bimolecular fluorescence complementation (BiFC) assays revealed that P7a protein interacted with Nicotiana benthamiana nuclear import factor importin α, suggesting that P7a is translocated into the nucleus by the classical importin α/β-dependent pathway. Moreover, P7a also interacted with the nucleolar protein fibrillarin. Mutations in the R-rich motif of P7a diminished P7a interactions with importin α and fibrillarin, influenced viral replication in Nicotiana benthamiana protoplasts and altered the symptom phenotype and viral RNA accumulation in Chenopodium amaranticolor plants. These results demonstrate that the R-rich motif of P7a is correlated with nuclear and nucleolar localization, viral replication and virus infection.
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Affiliation(s)
- Xiaohui Wang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Yanjing Zhang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Jin Xu
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Lindan Shi
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Huiyan Fan
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Chenggui Han
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Dawei Li
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Jialin Yu
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
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González I, Rakitina D, Semashko M, Taliansky M, Praveen S, Palukaitis P, Carr JP, Kalinina N, Canto T. RNA binding is more critical to the suppression of silencing function of Cucumber mosaic virus 2b protein than nuclear localization. RNA (NEW YORK, N.Y.) 2012; 18:771-82. [PMID: 22357910 PMCID: PMC3312564 DOI: 10.1261/rna.031260.111] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Previously, we found that silencing suppression by the 2b protein and six mutants correlated both with their ability to bind to double-stranded (ds) small RNAs (sRNAs) in vitro and with their nuclear/nucleolar localization. To further discern the contribution to suppression activity of sRNA binding and of nuclear localization, we have characterized the kinetics of in vitro binding to a ds sRNA, a single-stranded (ss) sRNA, and a micro RNA (miRNA) of the native 2b protein and eight mutant variants. We have also added a nuclear export signal (NES) to the 2b protein and assessed how it affected subcellular distribution and suppressor activity. We found that in solution native protein bound ds siRNA, miRNA, and ss sRNA with high affinity, at protein:RNA molar ratios ~2:1. Of the four mutants that retained suppressor activity, three showed sRNA binding profiles similar to those of the native protein, whereas the remaining one bound ss sRNA at a 2:1 molar ratio, but both ds sRNAs with 1.5-2 times slightly lower affinity. Three of the four mutants lacking suppressor activity failed to bind to any sRNA, whereas the remaining one bound them at far higher ratios. NES-tagged 2b protein became cytoplasmic, but suppression activity in patch assays remained unaffected. These results support binding to sRNAs at molar ratios at or near 2:1 as critical to the suppressor activity of the 2b protein. They also show that cytoplasmically localized 2b protein retained suppressor activity, and that a sustained nuclear localization was not required for this function.
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Affiliation(s)
| | - Daria Rakitina
- A. N. Belozersky Institute of Physico-Chemical Biology, Biological Faculty, Moscow State University, Leninskye Gory 119991, Russia
| | - Maria Semashko
- A. N. Belozersky Institute of Physico-Chemical Biology, Biological Faculty, Moscow State University, Leninskye Gory 119991, Russia
| | - Michael Taliansky
- The James Hutton Institute, Invergowrie, Dundee DD2 5DA, Scotland, United Kingdom
| | - Shelly Praveen
- Indian Agricultural Research institute, New Delhi 110-012, India
| | | | - John P. Carr
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Natalia Kalinina
- A. N. Belozersky Institute of Physico-Chemical Biology, Biological Faculty, Moscow State University, Leninskye Gory 119991, Russia
| | - Tomás Canto
- Centro de Investigaciones Biológicas, CIB, CSIC, Madrid 28040, Spain
- Corresponding author.E-mail .
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Semashko MA, González I, Shaw J, Leonova OG, Popenko VI, Taliansky ME, Canto T, Kalinina NO. The extreme N-terminal domain of a hordeivirus TGB1 movement protein mediates its localization to the nucleolus and interaction with fibrillarin. Biochimie 2012; 94:1180-8. [PMID: 22349738 DOI: 10.1016/j.biochi.2012.02.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 02/06/2012] [Indexed: 01/13/2023]
Abstract
The hordeiviral movement protein encoded by the first gene of the triple gene block (TGBp1) of Poa semilatent virus (PSLV), interacts with viral genomic RNAs to form RNP particles which are considered to be a form of viral genome capable of cell-to-cell and long-distance transport in infected plants. The PSLV TGBp1 contains a C-terminal NTPase/helicase domain (HELD) and an N-terminal extension region consisting of two structurally and functionally distinct domains: an extreme N-terminal domain (NTD) and an internal domain (ID). This study demonstrates that transient expression of TGBp1 fused to GFP in Nicotiana benthamiana leaves results in faint but obvious fluorescence in the nucleolus in addition to cytosolic distribution. Mutagenesis of the basic amino acids inside the NTD clusters A (116)KSKRKKKNKK(125) and B (175)KKATKKESKKQTK(187) reveals that these clusters are indispensable for nuclear and nucleolar targeting of PSLV TGBp1 and may contain nuclear and nucleolar localization signals or their elements. The PSLV TGBp1 is able to bind to fibrillarin, the major nucleolar protein (AtFib2 from Arabidopsis thaliana) in vitro. This protein-protein interaction occurs between the glycine-arginine-rich (GAR) domain of fibrillarin and the first 82 amino acid residues of TGBp1. The interaction of TGBp1 with fibrillarin is also visualized in vivo by bimolecular fluorescence complementation (BiFC) during co-expression of TGBp1 or its deletion mutants, and fibrillarin as fusions to different halves of YFP in N. benthamiana plants. The sites responsible for nuclear/nucleolar localization and fibrillarin binding, have been located within the intrinsically disordered TGBp1 NTD. These data could suggest that specific functions of hordeivirus TGBp1 may depend on its interaction with nucleolar components.
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Affiliation(s)
- Maria A Semashko
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninsky Gory, Moscow, 119992, Russia
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McGavin WJ, Mitchell C, Cock PJA, Wright KM, MacFarlane SA. Raspberry leaf blotch virus, a putative new member of the genus Emaravirus, encodes a novel genomic RNA. J Gen Virol 2012; 93:430-437. [DOI: 10.1099/vir.0.037937-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A new, segmented, negative-strand RNA virus with morphological and sequence similarities to other viruses in the genus Emaravirus was discovered in raspberry plants exhibiting symptoms of leaf blotch disorder, a disease previously attributed to the eriophyid raspberry leaf and bud mite (Phyllocoptes gracilis). The virus, tentatively named raspberry leaf blotch virus (RLBV), has five RNAs that each potentially encode a single protein on the complementary strand. RNAs 1, 2 and 3 encode, respectively, a putative RNA-dependent RNA polymerase, a glycoprotein precursor and the nucleocapsid. RNA4 encodes a protein with sequence similarity to proteins of unknown function that are encoded by the genomes of other emaraviruses. When expressed transiently in plants fused to green or red fluorescent protein, the RLBV P4 protein localized to the peripheral cell membrane and to punctate spots in the cell wall. These spots co-localized with GFP-tagged tobacco mosaic virus 30K cell-to-cell movement protein, which is itself known to associate with plasmodesmata. These results suggest that the P4 protein may be a movement protein for RLBV. The fifth RLBV RNA, encoding the P5 protein, is unique among the sequenced emaraviruses. The amino acid sequence of the P5 protein does not suggest any potential function; however, when expressed as a GFP fusion, it localized as small aggregates in the cytoplasm near to the periphery of the cell.
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Affiliation(s)
- Wendy J. McGavin
- Cell and Molecular Sciences Group, The James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
| | - Carolyn Mitchell
- Cell and Molecular Sciences Group, The James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
| | - Peter J. A. Cock
- Information and Computational Sciences Group, JHI, Invergowrie, Dundee DD2 5DA, UK
| | - Kathryn M. Wright
- Cell and Molecular Sciences Group, The James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
| | - Stuart A. MacFarlane
- Cell and Molecular Sciences Group, The James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
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Mathioudakis MM, Veiga R, Ghita M, Tsikou D, Medina V, Canto T, Makris AM, Livieratos IC. Pepino mosaic virus capsid protein interacts with a tomato heat shock protein cognate 70. Virus Res 2012; 163:28-39. [PMID: 21884738 DOI: 10.1016/j.virusres.2011.08.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 08/12/2011] [Accepted: 08/15/2011] [Indexed: 11/29/2022]
Abstract
Plant viral capsid proteins (CP) can be involved in virus movement, replication and symptom development as a result of their interaction with host factors. The identification of such interactions may thus provide information about viral pathogenesis. In this study, Pepino mosaic virus (PepMV) CP was used as bait to screen a tomato (Solanum lycopersicum) cDNA library for potential interactors in yeast. Of seven independent interacting clones, six were predicted to encode the C-termini of the heat shock cognate 70 (Hsc70) proteins. Three full length tomato Hsc70s (named Hsc70.1, .2, .3) were used to confirm the interaction in the yeast two hybrid assay and bimolecular fluorescent complementation (BiFC) in planta. The PepMV CP-Hsc70 interaction was confirmed only in the case of Hsc70.3 for both assays. In BiFC, the interaction was visualized in the cytoplasm and nucleus of agroinfiltrated Nicotiana benthamiana epidermal cells. During PepMV infection, Hsc70.3 mRNA levels were induced and protein accumulation increased at 48 and 72 h post inoculation. In transmission electron microscopy using immunogold labelling techniques, Hsc70 was detected to co-localize with virions in the phloem of PepMV-infected tomato leaves. These observations, together with the co-purification of Hsc70 with PepMV virions further support the notion of a PepMV CP/Hsc70 interaction during virus infection.
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Affiliation(s)
- Matthaios M Mathioudakis
- Department of Sustainable Agriculture, Mediterranean Agronomic Institute of Chania, Alsylio Agrokepion, GR-73100 Chania, Crete, Greece.
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