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Xu X, Lou Y, Liang K, Liu J, Wang Z, Chen B, Li W. The P2 nucleic acid binding protein of Sugarcane bacilliform virus is a viral pathogenic factor. PeerJ 2024; 12:e16982. [PMID: 38406282 PMCID: PMC10885806 DOI: 10.7717/peerj.16982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 01/30/2024] [Indexed: 02/27/2024] Open
Abstract
Background Saccharum spp. is the primary source of sugar and plays a significant role in global renewable bioenergy. Sugarcane bacilliform virus (SCBV) is one of the most important viruses infecting sugarcane, causing severe yield losses and quality degradation. It is of great significance to reveal the pathogenesis of SCBV and resistance breeding. However, little is known about the viral virulence factors or RNA silencing suppressors and the molecular mechanism of pathogenesis. Methods To systematically investigate the functions of the unknown protein P2 encoded by SCBV ORF2. Phylogenetic analysis was implemented to infer the evolutionary relationship between the P2 of SCBV and other badnaviruses. The precise subcellular localization of P2 was verified in the transient infiltrated Nicotiana benthamiana epidermal mesophyll cells and protoplasts using the Laser scanning confocal microscope (LSCM). The post-transcriptional gene silencing (PTGS) and transcriptional gene silencing (TGS) RNA silencing suppressor activity of P2 was analyzed, respectively. Furthermore, restriction digestion and RT-qPCR assays were conducted to verify the probable mechanism of P2 on repressing DNA methylation. To explore the pathogenicity of P2, a potato virus X-based viral vector was used to heterologously express SCBV P2 and the consequent H2O2 accumulation was detected by the 3,3'-diaminobenzidine (DAB) staining method. Results Phylogenetic analysis shows that SCBV has no obvious sequence similarity and low genetic relatedness to Badnavirus and Tungrovirus representatives. LSCM studies show that P2 is localized in both the cytoplasm and nucleus. Moreover, P2 is shown to be a suppressor of PTGS and TGS, which can not only repress ssRNA-induced gene silencing but also disrupt the host RNA-directed DNA methylation (RdDM) pathway. In addition, P2 can trigger an oxidative burst and cause typical hypersensitive-like response (HLR) necrosis in systemic leaves of N. benthamiana when expressed by PVX. Overall, our results laid a foundation for deciphering the molecular mechanism of SCBV pathogenesis and made progress for resistance breeding.
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Affiliation(s)
- Xiongbiao Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Yinian Lou
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Kaili Liang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Jingying Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Zhiyuan Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Baoshan Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi key Laboratory of Sugarcane biology, Province and Ministry Co-sponsored Collaborative Innovation Center of Canesugar Industry, College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Wenlan Li
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
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Liang KL, Liu JY, Bao YY, Wang ZY, Xu XB. Screening and Identification of Host Factors Interacting with the Virulence Factor P0 Encoded by Sugarcane Yellow Leaf Virus by Yeast Two-Hybrid Assay. Genes (Basel) 2023; 14:1397. [PMID: 37510302 PMCID: PMC10379860 DOI: 10.3390/genes14071397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 07/30/2023] Open
Abstract
Sugarcane yellow leaf virus (SCYLV), a member of the genus Polerovirus in the family Luteoviridae, causes severe damage and represents a great threat to sugarcane cultivation and sugar industry development. In this study, inoculation of Nicotiana benthamiana plants with a potato virus X (PVX)-based vector carrying the SCYLV P0 gene induced typical mosaic, leaf rolling symptoms and was associated with a hypersensitive-like response (HLR) necrosis symptom, which is accompanied with a systemic burst of H2O2 and also leads to higher PVX viral genome accumulation levels. Our results demonstrate that SCYLV P0 is a pathogenicity determinant and plays important roles in disease development. To further explore its function in pathogenic processes, a yeast two-hybrid assay was performed to screen the putative P0-interacting host factors. The recombinant plasmid pGBKT7-P0 was constructed as a bait and transformed into the yeast strain Y2HGold. The ROC22 cultivar (an important parental resource of the main cultivar in China) cDNA prey library was constructed and screened by co-transformation with the P0 bait. We identified 28 potential interacting partners including those involved in the optical signal path, plant growth and development, transcriptional regulation, host defense response, and viral replication. To our knowledge, this is the first time we have reported the host proteins interacting with the P0 virulence factor encoded by sugarcane yellow leaf virus. This study not only provides valuable insights into elucidating the molecular mechanism of the pathogenicity of SCYLV, but also sheds light on revealing the probable new pathogenesis of Polerovirus in the future.
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Affiliation(s)
- Kai-Li Liang
- Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning 530004, China
| | - Jing-Ying Liu
- Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning 530004, China
| | - Ying-Ying Bao
- College of Agriculture, Guangxi University, Nanning 530004, China
| | - Zhi-Yuan Wang
- Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning 530004, China
| | - Xiong-Biao Xu
- Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning 530004, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530004, China
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Zwolinski AM, Brigden A, Rey MEC. Differences in the 3' intergenic region and the V2 protein of two sequence variants of tomato curly stunt virus play an important role in disease pathology in Nicotiana benthamiana. PLoS One 2023; 18:e0286149. [PMID: 37220127 DOI: 10.1371/journal.pone.0286149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 05/10/2023] [Indexed: 05/25/2023] Open
Abstract
Tomato production in South Africa is threatened by the emergence of tomato curly stunt virus (ToCSV), a monopartite Begomovirus transmitted by the whitefly vector Bemisia tabaci (Genn.). We investigated the role of sequence differences present in the 3' intergenic region (IR) and the V2 coding region on the differing infectivity of ToCSV sequence variant isolates V30 and V22 in the model host Nicotiana benthamiana. Using virus mutant chimeras, we determined that the development of the upward leaf roll symptom phenotype is mediated by sequence differences present in the 3' IR containing the TATA-associated composite element. Sequence differences present in the V2 coding region are responsible for modulating disease severity and symptom recovery in V22-infected plants. Serine substitution of V22 V2 Val27 resulted in a significant increase in disease severity with reduced recovery, the first study to demonstrate the importance of this V2 residue in disease development. Two putative ORFs, C5 and C6, were identified using in silico analysis and detection of an RNA transcript spanning their coding region suggests that these ORFs may be transcribed during infection. Additional virus-derived RNA transcripts spanning multiple ORFs and crossing the boundaries of recognised polycistronic transcripts, as well as the origin of replication within the IR, were detected in ToCSV-infected plants providing evidence of bidirectional readthrough transcription. From our results, we conclude that the diverse responses of the model host to ToCSV infection is influenced by select sequence differences and our findings provide several avenues for further investigation into the mechanisms behind these responses to infection.
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Affiliation(s)
- Alexander M Zwolinski
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
| | - Alison Brigden
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
| | - Marie E C Rey
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
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Yang X, Luo X, Zhang Y, Zhang Z, OuYang X, Shi X, Lv X, Li F, Zhang S, Liu Y, Zhang D. Tomato chlorosis virus CPm protein is a pathogenicity determinant and suppresses host local RNA silencing induced by single-stranded RNA. Front Microbiol 2023; 14:1151747. [PMID: 37056753 PMCID: PMC10086252 DOI: 10.3389/fmicb.2023.1151747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/10/2023] [Indexed: 03/30/2023] Open
Abstract
IntroductionTomato chlorosis virus (ToCV) is a typical member of the genus Crinivirus, which severely threatens Solanaceae crops worldwide. The CPm protein encoded by ToCV has been reported to be associated with virus transmission by vectors and is involved in RNA silencing suppression, while the mechanisms remain ambiguous.MethodsHere, ToCV CPm was ectopically expressed by a Potato virus X (PVX) vector and infiltrated into Nicotiana benthamiana wild-type and GFP-transgenic16c plants.ResultsThe phylogenetic analysis showed that the CPm proteins encoded by criniviruses were distinctly divergent in amino acid sequences and predicted conserved domains, and the ToCV CPm protein possesses a conserved domain homologous to the TIGR02569 family protein, which does not occur in other criniviruses. Ectopic expression of ToCV CPm using a PVX vector resulted in severe mosaic symptoms followed by a hypersensitive-like response in N. benthamiana. Furthermore, agroinfiltration assays in N. benthamiana wilt type or GFP-transgenic 16c indicated that ToCV CPm protein effectively suppressed local RNA silencing induced by single-stranded but not double-stranded RNA, which probably resulted from the activity of binding double-stranded but not single-stranded RNA by ToCV CPm protein.ConclusionTaken together, the results of this study suggest that the ToCV CPm protein possesses the dual activities of pathogenicity and RNA silencing, which might inhibit host post-transcriptional gene silencing (PTGS)-mediated resistance and is pivotal in the primary process of ToCV infecting hosts.
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Affiliation(s)
- Xiao Yang
- Longping Branch, College of Biology, Hunan University, Changsha, Hunan, China
| | - Xiangwen Luo
- Longping Branch, College of Biology, Hunan University, Changsha, Hunan, China
- Key Laboratory of Pest Management of Horticultural Crop of Hunan Province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, Hunan, China
| | - Yu Zhang
- Key Laboratory of Pest Management of Horticultural Crop of Hunan Province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, Hunan, China
| | - Zhanhong Zhang
- Longping Branch, College of Biology, Hunan University, Changsha, Hunan, China
- Key Laboratory of Pest Management of Horticultural Crop of Hunan Province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, Hunan, China
| | - Xian OuYang
- Key Laboratory of Pest Management of Horticultural Crop of Hunan Province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, Hunan, China
| | - Xiaobin Shi
- Longping Branch, College of Biology, Hunan University, Changsha, Hunan, China
- Key Laboratory of Pest Management of Horticultural Crop of Hunan Province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, Hunan, China
| | - Xiaoyuan Lv
- Technical Center of Changsha Customs, Changsha, Hunan, China
| | - Fan Li
- College of Plant Protection, Yunnan Agricultural University, Kunming, China
| | - Songbai Zhang
- Longping Branch, College of Biology, Hunan University, Changsha, Hunan, China
- Key Laboratory of Pest Management of Horticultural Crop of Hunan Province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, Hunan, China
- *Correspondence: Songbai Zhang,
| | - Yong Liu
- Longping Branch, College of Biology, Hunan University, Changsha, Hunan, China
- Key Laboratory of Pest Management of Horticultural Crop of Hunan Province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, Hunan, China
- Yong Liu,
| | - Deyong Zhang
- Longping Branch, College of Biology, Hunan University, Changsha, Hunan, China
- Key Laboratory of Pest Management of Horticultural Crop of Hunan Province, Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, Hunan, China
- Deyong Zhang,
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Bahari A, Castillo AG, Safaie N, Bejarano ER, Luna AP, Shams-Bakhsh M. Functional Analysis of V2 Protein of Beet Curly Top Iran Virus. PLANTS (BASEL, SWITZERLAND) 2022; 11:3351. [PMID: 36501393 PMCID: PMC9736138 DOI: 10.3390/plants11233351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/23/2022] [Accepted: 11/26/2022] [Indexed: 06/17/2023]
Abstract
Geminivirus beet curly top Iran virus (BCTIV) is one of the main causal agents of the beet curly top disease in Iran and the newly established Becurtovirus genus type species. Although the biological features of known becurtoviruses are similar to those of curtoviruses, they only share a limited sequence identity, and no information is available on the function of their viral genes. In this work, we demonstrate that BCTIV V2, as the curtoviral V2, is also a local silencing suppressor in Nicotiana benthamiana and can delay the systemic silencing spreading, although it cannot block the cell-to-cell movement of the silencing signal to adjacent cells. BCTIV V2 shows the same subcellular localization as curtoviral V2, being detected in the nucleus and perinuclear region, and its ectopic expression from a PVX-derived vector also causes the induction of necrotic lesions in N. benthamiana, such as the ones produced during the HR, both at the local and systemic levels. The results from the infection of N. benthamiana with a V2 BCTIV mutant showed that V2 is required for systemic infection, but not for viral replication, in a local infection. Considering all these results, we can conclude that BCTIV V2 is a functional homologue of curtoviral V2 and plays a crucial role in viral pathogenicity and systemic movement.
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Affiliation(s)
- Atiyeh Bahari
- Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University (TMU), Tehran 336-14115, Iran
| | - Araceli G. Castillo
- Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento Biología Celular, Genética y Fisiología, Universidad de Málaga, 29010 Malaga, Spain
| | - Naser Safaie
- Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University (TMU), Tehran 336-14115, Iran
| | - Eduardo R. Bejarano
- Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento Biología Celular, Genética y Fisiología, Universidad de Málaga, 29010 Malaga, Spain
| | - Ana P. Luna
- Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento Biología Celular, Genética y Fisiología, Universidad de Málaga, 29010 Malaga, Spain
| | - Masoud Shams-Bakhsh
- Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University (TMU), Tehran 336-14115, Iran
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Gupta N, Reddy K, Gnanasekaran P, Zhai Y, Chakraborty S, Pappu HR. Functional characterization of a new ORF βV1 encoded by radish leaf curl betasatellite. FRONTIERS IN PLANT SCIENCE 2022; 13:972386. [PMID: 36212370 PMCID: PMC9546537 DOI: 10.3389/fpls.2022.972386] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 08/10/2022] [Indexed: 05/26/2023]
Abstract
Whitefly-transmitted begomoviruses infect and damage a wide range of food, feed, and fiber crops worldwide. Some of these viruses are associated with betasatellite molecules that are known to enhance viral pathogenesis. In this study, we investigated the function of a novel βV1 protein encoded by radish leaf curl betasatellite (RaLCB) by overexpressing the protein using potato virus X (PVX)-based virus vector in Nicotiana benthamiana. βV1 protein induced lesions on leaves, suggestive of hypersensitive response (HR), indicating cell death. The HR reaction induced by βV1 protein was accompanied by an increased accumulation of reactive oxygen species (ROS), free radicals, and HR-related transcripts. Subcellular localization through confocal microscopy revealed that βV1 protein localizes to the cellular periphery. βV1 was also found to interact with replication enhancer protein (AC3) of helper virus in the nucleus. The current findings suggest that βV1 functions as a protein elicitor and a pathogenicity determinant.
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Affiliation(s)
- Neha Gupta
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
| | - Kishorekumar Reddy
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Prabu Gnanasekaran
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
| | - Ying Zhai
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Hanu R. Pappu
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
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Wu H, Liu M, Kang B, Liu L, Hong N, Peng B, Gu Q. AC5 protein encoded by squash leaf curl China virus is an RNA silencing suppressor and a virulence determinant. Front Microbiol 2022; 13:980147. [PMID: 36060769 PMCID: PMC9437540 DOI: 10.3389/fmicb.2022.980147] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 08/05/2022] [Indexed: 11/26/2022] Open
Abstract
Squash leaf curl China virus (SLCCNV) is a bipartite Begomovirus. The function of the protein AC5, which is encoded by SLCCNV, is unknown. Here, we confirmed that the 172-amino acids (aa) long AC5 protein of SLCCNV could suppress single-stranded RNA but not double-stranded RNA-induced post-transcriptional gene silencing (PTGS). Furthermore, we determined that the C-terminal domain (96–172 aa) of the AC5 protein was responsible for RNA silencing suppressor (RSS) activity via deletion mutant analysis. The AC5 protein can reverse GFP silencing and inhibit systemic silencing of GFP by interfering with the systemic spread of the GFP silencing signal. The SLCCNV AC5 protein was localized to both the nucleus and cytoplasm of Nicotiana benthamiana cells. Furthermore, deletion analysis showed that the putative nuclear localization signal (NLS, 102–155 aa) was crucial for the RNA silencing suppression activity of AC5. In addition, the AC5 protein elicited a hypersensitive response and enhanced potoao virus X (PVX) RNA accumulation in infected N. benthamiana plants. Using the infectious clones of the SLCCNV and SLCCNV-AC5 null mutants, mutational analysis confirmed that knockout of the AC5 gene abolished SLCCNV-induced leaf curl symptoms, showing SLCCNV AC5 is also a virulence determinant.
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Affiliation(s)
- Huijie Wu
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, China
| | - Mei Liu
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, China
| | - Baoshan Kang
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, China
| | - Liming Liu
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, China
| | - Ni Hong
- College of Plant Science and Technology, Huazhong Agricultural University/Key Lab of Plant Pathology of Hubei Province, Wuhan, China
| | - Bin Peng
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, China
- Bin Peng,
| | - Qinsheng Gu
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, China
- *Correspondence: Qinsheng Gu,
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The Rep and C1 of Beet curly top Iran virus represent pathogenicity factors and induce hypersensitive response in Nicotiana benthamiana plants. Virus Genes 2022; 58:550-559. [PMID: 35960462 DOI: 10.1007/s11262-022-01927-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 07/26/2022] [Indexed: 10/15/2022]
Abstract
Beet curly top Iran virus (BCTIV) is a member of the genus Becurtovirus (Family Geminiviridae) with a circular single-strand DNA genome. BCTIV causes leaf curling and vein swelling symptoms in plants. However, the potential pathogenicity factor/s in BCTIV is/are not known. This study presents characterization of complementary-sense transcripts of BCTIV and the viral factors in directing the pathogenicity and hypersensitive response (HR) in Nicotiana benthamiana plants. In both local and systemic infection, splicing of the complementary transcripts of BCTIV was observed. Notably, a small number (8.3%) of transcripts were spliced to produce Rep (C1:C2) transcripts after deletion of 155 nt (position 1892-2046 from BCTIV). Expression of BCTIV genes in N. benthamiana using tobacco rattle virus (TRV)-based vector showed that Rep together with C1 are the main pathogenicity factors which cause typical viral leaf curling symptoms. In addition, the V2 caused a mild leaf curling, thickening, and asymmetric leaves, while the V1, V3, and C2 had no clear effect on the plant phenotype. Transient expression of individual viral genes showed that both the C1 and Rep trigger a HR response in N. benthamiana. The higher expression of HR marker genes, harpin-induced 1 (Hin1) and hypersensitivity-related (Hsr203JI), supported the role of C1 and Rep in HR response in plants. It is concluded that Rep and C1 are the main pathogenicity factors that also trigger HR response in plants.
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Li Q, Zhang Y, Lu W, Han X, Yang L, Shi Y, Li H, Chen L, Liu Y, Yang X, Shi Y. Identification and characterization of a new geminivirus from soybean plants and determination of V2 as a pathogenicity factor and silencing suppressor. BMC PLANT BIOLOGY 2022; 22:362. [PMID: 35869422 PMCID: PMC9308217 DOI: 10.1186/s12870-022-03745-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Soybean is one of the four major crops in China. The occurrence of viruses in soybean causes significant economic losses. RESULTS In this study, the soybean leaves from stay-green plants showing crinkle were collected for metatranscriptomic sequencing. A novel geminivirus, tentatively named soybean geminivirus A (SGVA), was identified in soybean stay-green plants. Sequence analysis of the full-length SGVA genome revealed a genome of 2762 nucleotides that contain six open reading frames. Phylogenetic analyses revealed that SGVA was located adjacent to the clade of begomoviruses in both the full genome-based and C1-based phylogenetic tree, while in the CP-based phylogenetic tree, SGVA was located adjacent to the clade of becurtoviruses. SGVA was proposed as a new recombinant geminivirus. Agroinfectious clone of SGVA was constructed. Typical systemic symptoms of curly leaves were observed at 11 dpi in Nicotiana benthamiana plants and severe dwarfism was observed after 3 weeks post inoculation. Expression of the SGVA encoded V2 and C1 proteins through a potato virus X (PVX) vector caused severe symptoms in N. benthamiana. The V2 protein inhibited local RNA silencing in co-infiltration assays in GFP transgenic 16C N. benthamiana plants. Further study revealed mild symptoms in N. benthamiana plants inoculated with SGVA-ZZ V2-STOP and SGVA-ZZ V2-3738AA mutants. Both the relative viral DNA and CP protein accumulation levels significantly decreased when compared with SGVA-inoculated plants. CONCLUSIONS This work identified a new geminivirus in soybean stay-green plants and determined V2 as a pathogenicity factor and silencing suppressor.
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Affiliation(s)
- Qinglun Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Yuyang Zhang
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Weiguo Lu
- Institute of Crops Molecular Breeding, Henan Academy of Agricultural Sciences/ National Centre for Plant Breeding, Zhengzhou, 450002, China
| | - Xiaoyu Han
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Lingling Yang
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Yajuan Shi
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Honglian Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Linlin Chen
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Yiqing Liu
- Guangdong Baiyun University, Guangzhou, 510550, China
| | - Xue Yang
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Yan Shi
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China.
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Chen J, Zheng L, Shi X, Zhang S, Tan X, Zhao X, Lu B, Ye Q, Miao S, Liu Y, Zhang D. The nonstructural protein NSs encoded by tomato zonate spot virus suppresses RNA silencing by interacting with NbSGS3. MOLECULAR PLANT PATHOLOGY 2022; 23:707-719. [PMID: 35184365 PMCID: PMC8995058 DOI: 10.1111/mpp.13192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 01/23/2022] [Accepted: 01/25/2022] [Indexed: 05/21/2023]
Abstract
Viral suppressors of RNA silencing (VSRs) are encoded by diverse viruses to counteract the RNA silencing-mediated defence mounted by the virus-infected host cells. In this study, we identified the NSs protein encoded by tomato zonate spot virus (TZSV) as a potent VSR, and used a potato virus X (PVX)-based heterologous expression system to demonstrate TZSV NSs as a viral pathogenicity factor that intensified PVX symptoms in Nicotiana benthamiana. We then used a yeast two-hybrid screen to identify the suppressor of gene silencing 3 protein of N. benthamiana (NbSGS3), a known component of the plant RNA silencing pathway, as an interaction partner of TZSV NSs. We verified this interaction in plant cells with bimolecular fluorescence complementation, subcellular colocalization, and co-immunoprecipitation. We further revealed that the NSs-NbSGS3 interaction correlated with the VSR activity of TZSV NSs. TZSV NSs reduced the concentration of NbSGS3 protein in plant cells, probably through the ubiquitination and autophagy pathways. Interestingly, TZSV infection, but not NSs overexpression, significantly up-regulated the NbSGS3 transcript levels. Our data indicate that TZSV NSs suppresses RNA silencing of the host plant and enhances TZSV pathogenicity through its interaction with NbSGS3. This study reveals a novel molecular mechanism of NSs-mediated suppression of plant host antiviral defence.
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Affiliation(s)
- Jianbin Chen
- Longping BranchGraduate School of Hunan UniversityChangshaChina
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
| | - Limin Zheng
- Longping BranchGraduate School of Hunan UniversityChangshaChina
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
| | - Xiaobin Shi
- Longping BranchGraduate School of Hunan UniversityChangshaChina
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
| | - Songbai Zhang
- Longping BranchGraduate School of Hunan UniversityChangshaChina
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
| | - Xinqiu Tan
- Longping BranchGraduate School of Hunan UniversityChangshaChina
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
| | - Xingyue Zhao
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
| | - Bingxin Lu
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
| | - Qian Ye
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
| | - Shuyue Miao
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
| | - Yong Liu
- Longping BranchGraduate School of Hunan UniversityChangshaChina
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
| | - Deyong Zhang
- Longping BranchGraduate School of Hunan UniversityChangshaChina
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangshaChina
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11
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Gupta K, Rishishwar R, Dasgupta I. The interplay of plant hormonal pathways and geminiviral proteins: partners in disease development. Virus Genes 2022; 58:1-14. [PMID: 35034268 DOI: 10.1007/s11262-021-01881-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 11/28/2021] [Indexed: 10/19/2022]
Abstract
Viruses belonging to the family Geminiviridae infect plants and are responsible for a number of diseases of crops in the tropical and sub-tropical regions of the World. The innate immune response of the plant assists in its defense against such viral pathogens by the recognition of pathogen/microbe-associated molecular patterns through pattern-recognition receptors. Phytohormone signalling pathways play a vital role in plant defense responses against these devastating viruses. Geminiviruses, however, have developed counter-defense strategies that prevail over the above defense pathways. The proteins encoded by geminiviruses act as suppressors of plant immunity by interacting with the signalling components of several hormones. In this review we focus on the molecular interplay of phytohormone pathways and geminiviral infection and try to find interesting parallels with similar mechanisms known in other plant-infecting viruses and strengthen the argument that this interplay is necessary for disease development.
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Affiliation(s)
- Kanika Gupta
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, -110021, India
| | - Rashmi Rishishwar
- Department of Botany, Bhagat Singh Government P.G. College, Jaora, Ratlam, Madhya Pradesh, 457226, India
| | - Indranil Dasgupta
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, -110021, India.
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12
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Wang L, Tian P, Yang X, Zhou X, Zhang S, Li C, Yang X, Liu Y. Key Amino Acids for Pepper Vein Yellows Virus P0 Protein Pathogenicity, Gene Silencing, and Subcellular Localization. Front Microbiol 2021; 12:680658. [PMID: 34589062 PMCID: PMC8475269 DOI: 10.3389/fmicb.2021.680658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/28/2021] [Indexed: 11/13/2022] Open
Abstract
Pepper vein yellows virus (PeVYV) is a newly recognized Polerovirus extracted from Chinese pepper. The symptoms of PeVYV-infested pepper plants comprise intervein yellow staining, leaf curl formation and other malformations, and leaf internodal shrinkage, but the roles of the viral proteins remain undetermined. The P0 protein of the genus Polerovirus has established post-transcriptional gene silencing (PTGS) activity. This investigation focused on the PeVYV-encoded P0 protein and assessed its potential virulence capacity, PTGS activity, and tendencies to localize in the nucleus. This study revealed that P0 influenced the pathogenic properties of a specific heterologous potato virus X. In addition, P0 proteins impaired local gene silencing, although they did not regulate generalized gene silencing within Nicotiana benthamiana 16c plants. Furthermore, P0 proteins localized mainly in the nucleus, particularly in the nucleolus. P0 deletion mutagenesis demonstrated that the F-box motif (56–72 amino acids, AAs) of P0 was essential for symptom determination, inhibition of PTGS, and subcellular localization. Mutation analysis of the F-box motif of P0 protein indicated that AA 57 of the P0 protein was a pivotal site in symptom development and that AA 56 of the P0 protein was indispensable for inhibiting PTGS and subcellular localization. The outcomes obtained here suggest that further studies should be conducted on the molecular mechanisms of amino acids of the F-box domain of P0 protein in the interaction of PeVYV with plants.
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Affiliation(s)
- Lishuang Wang
- College of Plant Protection, Hunan Agricultural University, Changsha, China.,Institute of Plant Protection, Guizhou Academy of Agricultural Sciences, Guiyang, China
| | - Peijie Tian
- College of Plant Protection, Hunan Agricultural University, Changsha, China
| | - Xiuling Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Xueping Zhou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Songbai Zhang
- Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha, China
| | - Chun Li
- Institute of Plant Protection, Guizhou Academy of Agricultural Sciences, Guiyang, China
| | - Xuehui Yang
- Institute of Plant Protection, Guizhou Academy of Agricultural Sciences, Guiyang, China
| | - Yong Liu
- College of Plant Protection, Hunan Agricultural University, Changsha, China.,Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha, China
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13
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Zhao W, Zhou Y, Zhou X, Wang X, Ji Y. Host GRXC6 restricts Tomato yellow leaf curl virus infection by inhibiting the nuclear export of the V2 protein. PLoS Pathog 2021; 17:e1009844. [PMID: 34398921 PMCID: PMC8389846 DOI: 10.1371/journal.ppat.1009844] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 08/26/2021] [Accepted: 07/27/2021] [Indexed: 11/27/2022] Open
Abstract
Geminiviruses cause serious symptoms and devastating losses in crop plants. With a circular, single-stranded DNA genome, geminiviruses multiply their genomic DNA in the nucleus, requiring the nuclear shuttling of viral proteins and viral genomic DNAs. Many host factors, acting as proviral or antiviral factors, play key roles in geminivirus infections. Here, we report the roles of a tomato glutaredoxin (GRX), SlGRXC6, in the infection of Tomato yellow leaf curl virus (TYLCV), a single-component geminivirus. The V2 protein of TYLCV specifically and preferentially interacts with SlGRXC6 among the 55-member tomato GRX family that are broadly involved in oxidative stress responses, plant development, and pathogen responses. We show that overexpressed SlGRXC6 increases the nuclear accumulation of V2 by inhibiting its nuclear export and, in turn, inhibits trafficking of the V1 protein and viral genomic DNA. Conversely, the silenced expression of SlGRXC6 leads to an enhanced susceptibility to TYLCV. SlGRXC6 is also involved in symptom development as we observed a positive correlation where overexpression of SlGRXC6 promotes while knockdown of SlGRXC6 expression inhibits plant growth. We further showed that SlGRXC6 works with SlNTRC80, a tomato NADPH-dependent thioredoxin reductase, to regulate plant growth. V2 didn’t interact with SlNTRC80 but competed with SlNTR80 for binding to SlGRXC6, suggesting that the V2-disrupted SlGRXC6-SlNTRC80 interaction is partially responsible for the virus-caused symptoms. These results suggest that SlGRXC6 functions as a host restriction factor that inhibits the nuclear trafficking of viral components and point out a new way to control TYLCV infection by targeting the V2-SlGRXC6 interaction. Geminiviruses infect numerous crops, induce a wide range of symptoms, and cause tremendous crop losses annually. Tomato yellow leaf curl virus (TYLCV), a single-component geminivirus, is a causative agent leading to one of the most devastating tomato diseases in the world. As a single-stranded DNA virus, genomic replication occurs in the nucleus and therefore, the nuclear shuttling is a critical step of viral infection. The V2 protein of TYLCV is involved in symptom development and viral trafficking, among other steps, and hijacks host proteins for executing its functions. Nevertheless, host factors involved in the V2-mediated functions are not well addressed. We show that tomato GRXC6 (SlGRXC6) functions as a restriction factor of TYLCV infection by interacting with and preventing V2 from moving out of the nucleus, leading to the inhibited V2-mediated nuclear export of V1 and the V1-viral DNA complex. SlGRXC6 also contributes to symptom development via its interaction with SINTRC80. V2 sequesters SlGRXC6 from forming the SlGRXC6-SlNTRC80 complex and regulates plant growth. Our work, therefore, identified a new host partner of V2 and revealed the mechanisms whereby V2 functions as a pathogenicity determinant and can be targeted for virus control.
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Affiliation(s)
- Wenhao Zhao
- Key Lab of Food Quality and Safety of Jiangsu Province—State Key Laboratory Breeding Base, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Yijun Zhou
- Key Lab of Food Quality and Safety of Jiangsu Province—State Key Laboratory Breeding Base, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xueping Zhou
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- * E-mail: (XZ); (XW); (YJ)
| | - Xiaofeng Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail: (XZ); (XW); (YJ)
| | - Yinghua Ji
- Key Lab of Food Quality and Safety of Jiangsu Province—State Key Laboratory Breeding Base, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- * E-mail: (XZ); (XW); (YJ)
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14
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Gupta N, Reddy K, Bhattacharyya D, Chakraborty✉ S. Plant responses to geminivirus infection: guardians of the plant immunity. Virol J 2021; 18:143. [PMID: 34243802 PMCID: PMC8268416 DOI: 10.1186/s12985-021-01612-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/29/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Geminiviruses are circular, single-stranded viruses responsible for enormous crop loss worldwide. Rapid expansion of geminivirus diversity outweighs the continuous effort to control its spread. Geminiviruses channelize the host cell machinery in their favour by manipulating the gene expression, cell signalling, protein turnover, and metabolic reprogramming of plants. As a response to viral infection, plants have evolved to deploy various strategies to subvert the virus invasion and reinstate cellular homeostasis. MAIN BODY Numerous reports exploring various aspects of plant-geminivirus interaction portray the subtlety and flexibility of the host-pathogen dynamics. To leverage this pool of knowledge towards raising antiviral resistance in host plants, a comprehensive account of plant's defence response against geminiviruses is required. This review discusses the current knowledge of plant's antiviral responses exerted to geminivirus in the light of resistance mechanisms and the innate genetic factors contributing to the defence. We have revisited the defence pathways involving transcriptional and post-transcriptional gene silencing, ubiquitin-proteasomal degradation pathway, protein kinase signalling cascades, autophagy, and hypersensitive responses. In addition, geminivirus-induced phytohormonal fluctuations, the subsequent alterations in primary and secondary metabolites, and their impact on pathogenesis along with the recent advancements of CRISPR-Cas9 technique in generating the geminivirus resistance in plants have been discussed. CONCLUSIONS Considering the rapid development in the field of plant-virus interaction, this review provides a timely and comprehensive account of molecular nuances that define the course of geminivirus infection and can be exploited in generating virus-resistant plants to control global agricultural damage.
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Affiliation(s)
- Neha Gupta
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Kishorekumar Reddy
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Dhriti Bhattacharyya
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Supriya Chakraborty✉
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
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15
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Sun K, Liang Y, Zhong X, Hu X, Zhang P, Yu X. Nightshade Curly Top Virus: A Possible New Virus of the Genus Topocuvirus Infecting Solanum nigrum in China. PLANT DISEASE 2021; 105:1006-1012. [PMID: 33026306 DOI: 10.1094/pdis-03-20-0572-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Virus-like symptoms, including leaf deformation and curling, were observed on nightshade (Solanum nigrum) in Zhejiang Province, China. To identify possible pathogenic viruses or viroids, a symptomatic sample was subjected to deep sequencing of small interfering RNAs. Assembly of the resulting sequences led to identification of a novel geminivirus, provisionally designated nightshade curly top virus (NCTV). The complete genomic DNA sequence is 2,867 nucleotides and encodes seven open reading frames. NCTV shares 77.1% overall nucleotide sequence identity, 86.3% coat protein amino acid identity, and 78.9% replication-associated protein amino acid sequence identity with Tomato pseudo-curly top virus, a member of the genus Topocuvirus. PCR screening of nightshade field isolates indicated that NCTV is widely distributed in Zhejiang. Agrobacterium-mediated inoculation revealed that NCTV is highly infectious to Nicotiana benthamiana, S. nigrum, S. lycopersicum, and S. tuberosum. Based on pairwise comparisons and phylogenetic analyses, NCTV is proposed as a provisional member of the genus Topocuvirus.
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Affiliation(s)
- Kai Sun
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Sciences, China Jiliang University, Hangzhou 310018, Zhejiang Province, People's Republic of China
| | - Yan Liang
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Sciences, China Jiliang University, Hangzhou 310018, Zhejiang Province, People's Republic of China
| | - Xueting Zhong
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Sciences, Huzhou University, Huzhou 313000, People's Republic of China
| | - Xuenan Hu
- Guangzhou Customs Technology Center, Guangzhou 510623, People's Republic of China
| | - Pengjun Zhang
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Sciences, China Jiliang University, Hangzhou 310018, Zhejiang Province, People's Republic of China
| | - Xiaoping Yu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Sciences, China Jiliang University, Hangzhou 310018, Zhejiang Province, People's Republic of China
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16
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Basu S, Singh AK, Singh D, Sahu SK, Chakraborty S. Role of viral suppressors governing asymmetric synergism between tomato-infecting begomoviruses. Appl Microbiol Biotechnol 2021; 105:1107-1121. [PMID: 33417040 DOI: 10.1007/s00253-020-11070-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 12/01/2020] [Accepted: 12/17/2020] [Indexed: 11/29/2022]
Abstract
Mixed viral infections are common in fields and frequently exacerbate disease severity via synergistic interactions among individual viral genomic components leading to major crop loss. Two predominant species of tomato-infecting begomoviruses, Tomato leaf curl New Delhi virus (ToLCNDV) and Tomato leaf curl Gujarat virus (ToLCGuV), are known to cause severe leaf curl disease of tomato in India. Previously, we have demonstrated asymmetric synergism between these two distinct begomovirus species during mixed infection in solanaceous hosts. In the present study, we have identified the underlying proteins that positively regulate asymmetric synergism and their effect on plant defense machinery. During co-infection, the AC2 and AV2 of ToLCGuV enhanced ToLCNDV DNA accumulation in Nicotiana benthamiana as well as in their natural host, tomato. Furthermore, we found that AC2 and AV2 of ToLCNDV and AV2 of ToLCGuV play a critical role in suppression of post transcriptional gene silencing (PTGS) machinery. Taken together, AC2 and AV2 encoded proteins of ToLCGuV are the crucial viral factors promoting asymmetric synergism with ToLCNDV. KEY POINTS: • Begomoviral suppressors play vital roles in viral synergism. • AC2 and AV2 of ToLCGuV asymmetrically enhance ToLCNDV accumulation. • AC2 and AV2 of ToLCNDV and ToLCGuV AV2 are major PTGS suppressors.
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Affiliation(s)
- Saumik Basu
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Ashish Kumar Singh
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India
| | - Divya Singh
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India
| | - Sanjeeb Kumar Sahu
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India
- Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India.
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17
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Li M, Li C, Jiang K, Li K, Zhang J, Sun M, Wu G, Qing L. Characterization of Pathogenicity-Associated V2 Protein of Tobacco Curly Shoot Virus. Int J Mol Sci 2021; 22:E923. [PMID: 33477652 PMCID: PMC7831499 DOI: 10.3390/ijms22020923] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 11/17/2022] Open
Abstract
V2 proteins encoded by some whitefly-transmitted geminiviruses were reported to be functionally important proteins. However, the functions of the V2 protein of tobacco curly shoot virus (TbCSV), a monopartite begomovirus that causes leaf curl disease on tomato and tobacco in China, remains to be characterized. In our report, an Agrobacterium infiltration-mediated transient expression assay indicated that TbCSV V2 can suppress local and systemic RNA silencing and the deletion analyses demonstrated that the amino acid region 1-92 of V2, including the five predicted α-helices, are required for local RNA silencing suppression. Site-directed substitutions showed that the conserved basic and ring-structured amino acids in TbCSV V2 are critical for its suppressor activity. Potato virus X-mediated heteroexpression of TbCSV V2 in Nicotiana benthamiana induced hypersensitive response-like (HR-like) cell death and systemic necrosis in a manner independent of V2's suppressor activity. Furthermore, TbCSV infectious clone mutant with untranslated V2 protein (TbCSV∆V2) could not induce visual symptoms, and coinfection with betasatellite (TbCSB) could obviously elevate the viral accumulation and symptom development. Interestingly, symptom recovery occurred at 15 days postinoculation (dpi) and onward in TbCSV∆V2/TbCSB-inoculated plants. The presented work contributes to understanding the RNA silencing suppression activity of TbCSV V2 and extends our knowledge of the multifunctional role of begomovirus-encoded V2 proteins during viral infections.
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Affiliation(s)
- Mingjun Li
- Correspondence: (M.L.); (L.Q.); Tel.: +86-023-68250517 (L.Q.)
| | | | | | | | | | | | | | - Ling Qing
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing 400716, China; (C.L.); (K.J.); (K.L.); (J.Z.); (M.S.); (G.W.)
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18
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An JW, Lee JH, Choi S, Venkatesh J, Kim JM, Kwon JK, Kang BC. Identification of the determinant of tomato yellow leaf curl Kanchanaburi virus infectivity in tomato. Virus Res 2021; 291:198192. [PMID: 33058965 DOI: 10.1016/j.virusres.2020.198192] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/24/2020] [Accepted: 10/06/2020] [Indexed: 12/20/2022]
Abstract
Geminiviruses cause devastating diseases in solanaceous crops, with the bipartite begomoviruses tomato yellow leaf curl Kanchanaburi virus (TYLCKaV) and pepper yellow leaf curl Thailand virus (PYLCThV) major threats in Southeast Asia. To determine the molecular mechanism of geminivirus infection, we constructed infectious clones of TYLCKaV and PYLCThV. Both constructs infected Nicotiana benthamiana, but only TYLCKaV could infect Solanum lycopersicum 'A39'. A genome-swapping of TYLCKaV with PYLCThV revealed the TYLCKaV-B genome segment as the determinant of TYLCKaV infectivity in tomato. We constructed five geminivirus clones with chimeric TYLCKaV-B and PYLCThV-B genome segments to narrow down the region determining TYLCKaV infectivity in tomato. Only chimeric clones carrying the TYLCKaV intergenic region (IR) showed infectivity in S. lycopersicum 'A39', indicating that the IR of TYLCKaV-B is essential for TYLCKaV infectivity in tomato. Our results provide a foundation for elucidating the molecular mechanism of geminivirus infection in plants.
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Affiliation(s)
- Jong-Wook An
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Joung-Ho Lee
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Seula Choi
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jelli Venkatesh
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jung-Min Kim
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jin-Kyung Kwon
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Byoung-Cheorl Kang
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
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19
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Liu Q, Li Y, Xu K, Li D, Hu H, Zhou F, Song P, Yu Y, Wei Q, Liu Q, Wang W, Bu R, Sun H, Wang X, Hao J, Li H, Li C. Clay nanosheet-mediated delivery of recombinant plasmids expressing artificial miRNAs via leaf spray to prevent infection by plant DNA viruses. HORTICULTURE RESEARCH 2020; 7:179. [PMID: 33328436 PMCID: PMC7603507 DOI: 10.1038/s41438-020-00400-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/26/2020] [Accepted: 09/01/2020] [Indexed: 05/10/2023]
Abstract
Whitefly-transmitted begomoviruses are economically important plant pathogens that cause severe problems in many crop plants, such as tomato, papaya, cotton, and tobacco. Tomato yellow leaf curl virus (TYLCV) is a typical monopartite begomovirus that has been extensively studied, but methods that can efficiently control begomoviruses are still scarce. In this study, we combined artificial microRNA (amiRNA)-mediated silencing technology and clay nanosheet-mediated delivery by spraying and developed a method for efficiently preventing TYLCV infection in tomato plants. We designed three amiRNAs that target different regions of TYLCV to silence virus-produced transcripts. Three plant expression vectors expressing pre-amiRNAs were constructed, and recombinant plasmid DNAs (pDNAs) were loaded onto nontoxic and degradable layered double hydroxide (LDH) clay nanosheets. LDH nanosheets containing multiple pDNAs were sprayed onto plant leaves. We found that the designed amiRNAs were significantly accumulated in leaves 7 days after spraying, while the pDNAs were sustainably detected for 35 days after the spray, suggesting that the LDH nanosheets released pDNAs in a sustained manner, protected pDNAs from degradation and efficiently delivered pDNAs into plant cells. Importantly, when the LDH nanosheets coated with pDNAs were sprayed onto plants infected by TYLCV, both the disease severity and TYLCV viral concentration in sprayed plants were significantly decreased during the 35 days, while the levels of H2O2 were significantly increased in those plants. Taken together, these results indicate that LDH nanosheets loaded with pDNAs expressing amiRNAs can be a sustainable and promising tool for begomovirus control.
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Affiliation(s)
- Qili Liu
- Postdoctoral Research Base, Henan Institute of Science and Technology, Xinxiang, China
- College of Plant Protection, Henan Agricultural University, Zhengzhou, Henan, China
- Henan Engineering Research Center of Crop Genome Editing, Henan Institute of Science and Technology, Xinxiang, China
| | - Yanpeng Li
- State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou, China
| | - Kedong Xu
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou, China
| | - Dongxiao Li
- Henan Engineering Research Center of Crop Genome Editing, Henan Institute of Science and Technology, Xinxiang, China
| | - Haiyan Hu
- Henan Engineering Research Center of Crop Genome Editing, Henan Institute of Science and Technology, Xinxiang, China
| | - Feng Zhou
- Henan Engineering Research Center of Crop Genome Editing, Henan Institute of Science and Technology, Xinxiang, China
| | - Puwen Song
- Henan Engineering Research Center of Crop Genome Editing, Henan Institute of Science and Technology, Xinxiang, China
| | - Yongang Yu
- Henan Engineering Research Center of Crop Genome Editing, Henan Institute of Science and Technology, Xinxiang, China
| | - Qichao Wei
- Henan Engineering Research Center of Crop Genome Editing, Henan Institute of Science and Technology, Xinxiang, China
| | - Qian Liu
- Postdoctoral Research Base, Henan Institute of Science and Technology, Xinxiang, China
| | - Weipeng Wang
- Postdoctoral Research Base, Henan Institute of Science and Technology, Xinxiang, China
| | - Ruifang Bu
- Henan Engineering Research Center of Crop Genome Editing, Henan Institute of Science and Technology, Xinxiang, China
| | - Haili Sun
- Henan Engineering Research Center of Crop Genome Editing, Henan Institute of Science and Technology, Xinxiang, China
| | - Xiaohui Wang
- State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou, China.
| | - Jianjun Hao
- School of Food and Agriculture, The University of Maine, Orono, ME, 04469, USA
| | - Honglian Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou, Henan, China.
| | - Chengwei Li
- Postdoctoral Research Base, Henan Institute of Science and Technology, Xinxiang, China.
- Henan Engineering Research Center of Crop Genome Editing, Henan Institute of Science and Technology, Xinxiang, China.
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou, China.
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20
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Vinoth Kumar R, Shivaprasad PV. Plant-virus-insect tritrophic interactions: insights into the functions of geminivirus virion-sense strand genes. Proc Biol Sci 2020; 287:20201846. [PMID: 33049166 DOI: 10.1098/rspb.2020.1846] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The genome of the plant-infecting viruses in the family Geminiviridae is composed of one or two circular single stranded DNA of approximately 2.7-5.2 kb in length. These viruses have emerged as the most devastating pathogen infecting a large number of crops and weeds across the continents. They code for fewer open reading frames (ORFs) through the generation of overlapping transcripts derived from the bidirectional viral promoters. Members of geminiviruses code for up to four ORFs in the virion-sense strand, and their gene expression is regulated by various cis-elements located at their promoters in the intergenic region. These viral proteins perform multiple functions at every stage of the viral life cycle such as virus transport, insect-mediated virus transmission and suppression of host defence. They impede the host's multi-layered antiviral mechanisms including gene silencing (at transcriptional and post-transcriptional levels) and hypersensitive response. This review summarizes the essential role of virion-sense strand encoded proteins in transport of viral genomes within and between plant cells, countering defence in hosts (both plants and the insects), and also in the ubiquitous role in vector-mediated transmission. We highlight the significance of their pro-viral activities in manipulating host-derived innate immune responses and the interaction with whitefly-derived proteins. We also discuss the current knowledge on virus replication and transcription within the insect body.
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Affiliation(s)
- R Vinoth Kumar
- National Centre for Biological Sciences (NCBS), Tata Institute of Fundamental Research (TIFR), GKVK campus, Bengaluru 560065, Karnataka, India
| | - P V Shivaprasad
- National Centre for Biological Sciences (NCBS), Tata Institute of Fundamental Research (TIFR), GKVK campus, Bengaluru 560065, Karnataka, India
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21
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Luna AP, Romero-Rodríguez B, Rosas-Díaz T, Cerero L, Rodríguez-Negrete EA, Castillo AG, Bejarano ER. Characterization of Curtovirus V2 Protein, a Functional Homolog of Begomovirus V2. FRONTIERS IN PLANT SCIENCE 2020; 11:835. [PMID: 32636860 PMCID: PMC7318802 DOI: 10.3389/fpls.2020.00835] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 05/25/2020] [Indexed: 05/30/2023]
Abstract
Geminiviruses are single-stranded DNA plant viruses with circular genomes packaged within geminate particles. Among the Geminiviridae family, Begomovirus and Curtovirus comprise the two best characterized genera. Curtovirus and Old World begomovirus possess similar genome structures with six to seven open-reading frames (ORF). Among them, begomovirus and curtovirus V2 ORFs share the same location in the viral genome, encode proteins of similar size, but show extremely poor sequence homology between the genera. V2 from Beet curly top virus (BCTV), the model species for the Curtovirus genus, as it begomoviral counterpart, suppresses post-transcriptional gene silencing (PTGS) by impairing the RDR6/SGS3 pathway and localizes in the nucleus spanning from the perinuclear region to the cell periphery. By aminoacid sequence comparison we have identified that curtoviral and begomoviral V2 proteins shared two hydrophobic domains and a putative phosphorylation motif. These three domains are essential for BCTV V2 silencing suppression activity, for the proper nuclear localization of the protein and for systemic infection. The lack of suppression activity in the mutated versions of V2 is complemented by the impaired function of RDR6 in Nicotiana benthamiana but the ability of the viral mutants to produce a systemic infection is not recovered in gene silencing mutant backgrounds. We have also demonstrated that, as its begomoviral homolog, V2 from BCTV is able to induce systemic symptoms and necrosis associated with a hypersensitive response-like (HR-like) when expressed from Potato virus X vector in N. benthamiana, and that this pathogenicity activity does not dependent of its ability to supress PTGS.
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Affiliation(s)
- Ana P Luna
- Departamento de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain
| | - Beatriz Romero-Rodríguez
- Departamento de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain
| | - Tábata Rosas-Díaz
- Departamento de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain
| | - Laura Cerero
- Departamento de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain
| | - Edgar A Rodríguez-Negrete
- CONACyT, Departamento de Biotecnología Agrícola, Instituto Politécnico Nacional, CIIDIR-Unidad Sinaloa, Guasave, Mexico
| | - Araceli G Castillo
- Departamento de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain
| | - Eduardo R Bejarano
- Departamento de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain
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Luna AP, Lozano-Durán R. Geminivirus-Encoded Proteins: Not All Positional Homologs Are Made Equal. Front Microbiol 2020; 11:878. [PMID: 32431689 PMCID: PMC7214792 DOI: 10.3389/fmicb.2020.00878] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 04/15/2020] [Indexed: 01/02/2023] Open
Affiliation(s)
- Ana P. Luna
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” (IHSM-UMA-CSIC), Area de Genética, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Rosa Lozano-Durán
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
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23
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Gong YN, Tang RQ, Zhang Y, Peng J, Xian O, Zhang ZH, Zhang SB, Zhang DY, Liu H, Luo XW, Liu Y. The NIa-Protease Protein Encoded by the Pepper Mottle Virus Is a Pathogenicity Determinant and Releases DNA Methylation of Nicotiana benthamiana. Front Microbiol 2020; 11:102. [PMID: 32153517 PMCID: PMC7047827 DOI: 10.3389/fmicb.2020.00102] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/17/2020] [Indexed: 12/12/2022] Open
Abstract
It is well documented that the canonical function of NIa-protease (NIa-Pro) of the potyviruses is responsible for cleaving the viral polyprotein into functional proteins. Although NIa-Pro is vital for the infection cycle of potyviruses, the function of NIa-Pro in the interaction of the potyvirus host is not clear. In this study, NIa-Pro is ectopically expressed from a potato virus X (PVX) vector and infiltrates Nicotiana benthamiana wild type and 16-TGS. The pathogenicity and inhibition of host transcriptional gene silencing (TGS) are characterized. Ectopic expression of NIa-Pro from a PVX vector resulted in severe mosaic symptoms followed by a hypersensitive-like response in N. benthamiana. Furthermore, PepMoV NIa-Pro was able to reverse established TGS of a green fluorescent protein transgene by reducing methylation of promoter sequences in N. benthamiana and possessed the capacity to interfere with the global methylation of N. benthamiana. Taken together, the results of this study likely suggest that PepMoV NIa-Pro is a pathogenicity determinant and a potent suppressor of host TGS and suggest that NIa-Pro may employ novel mechanisms to suppress host antiviral defenses. To the best of our knowledge, this is the first report of a plant RNA virus modulating host TGS in a novel manner by interfering with the establishment of the methylation step of the plant DNA methylation pathway.
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Affiliation(s)
- Yi-Nuo Gong
- Longping Branch, Graduate School of Hunan University, Changsha, China
| | - Ru-Qing Tang
- Hunan Academy of Agricultural Sciences, Changsha, China
| | - Yu Zhang
- Longping Branch, Graduate School of Hunan University, Changsha, China
| | - Jing Peng
- Hunan Academy of Agricultural Sciences, Changsha, China
| | - OuYang Xian
- Hunan Academy of Agricultural Sciences, Changsha, China
| | | | - Song-Bai Zhang
- Longping Branch, Graduate School of Hunan University, Changsha, China.,Hunan Academy of Agricultural Sciences, Changsha, China
| | - De-Yong Zhang
- Longping Branch, Graduate School of Hunan University, Changsha, China.,Hunan Academy of Agricultural Sciences, Changsha, China
| | - Hui Liu
- National Agro-Tech Extension and Service Center, Beijing, China
| | - Xiang-Wen Luo
- Hunan Academy of Agricultural Sciences, Changsha, China
| | - Yong Liu
- Longping Branch, Graduate School of Hunan University, Changsha, China.,Hunan Academy of Agricultural Sciences, Changsha, China
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Li P, Jing C, Ren H, Jia Z, Ghanem H, Wu G, Li M, Qing L. Analysis of Pathogenicity and Virulence Factors of Ageratum leaf curl Sichuan virus. FRONTIERS IN PLANT SCIENCE 2020; 11:527787. [PMID: 33042171 PMCID: PMC7527423 DOI: 10.3389/fpls.2020.527787] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 08/28/2020] [Indexed: 05/05/2023]
Abstract
Ageratum leaf curl Sichuan virus (ALCScV) is a novel monopartite begomovirus, which was identified from Ageratum conyzoides plants in Sichuan Province, China. In this study, we showed that ALCScV can induce typical dwarf and downward leaf-curling symptoms in Ageratum conyzoides, Helianthus annuus, and Nicotiana benthamiana plants and that the noncognate betasatellite can enhance disease symptoms and increase viral accumulation. Expression of the ALCScV-encoded V2, C1, and C4 proteins through a Potato virus X (PVX) vector caused severe symptoms in N. benthamiana. Further study revealed no symptoms in N. benthamiana plants inoculated with infectious ALCScV clones lacking the C4 protein and that the relative viral DNA accumulation levels significantly decreased when compared with ALCScV-inoculated plants. Thus, our mutational analyses demonstrated that C4 is a pathogenicity determinant that plays key roles in symptom formation and virus accumulation. Furthermore, we also demonstrated that the second glycine of C4 was critical for ALCScV pathogenicity.
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25
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Guerrero J, Regedanz E, Lu L, Ruan J, Bisaro DM, Sunter G. Manipulation of the Plant Host by the Geminivirus AC2/C2 Protein, a Central Player in the Infection Cycle. FRONTIERS IN PLANT SCIENCE 2020; 11:591. [PMID: 32508858 PMCID: PMC7248346 DOI: 10.3389/fpls.2020.00591] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 04/20/2020] [Indexed: 05/22/2023]
Abstract
Geminiviruses are a significant group of emergent plant DNA viruses causing devastating diseases in food crops worldwide, including the Southern United States, Central America and the Caribbean. Crop failure due to geminivirus-related disease can be as high as 100%. Improved global transportation has enhanced the spread of geminiviruses and their vectors, supporting the emergence of new, more virulent recombinant strains. With limited coding capacity, geminiviruses encode multifunctional proteins, including the AC2/C2 gene that plays a central role in the viral replication-cycle through suppression of host defenses and transcriptional regulation of the late viral genes. The AC2/C2 proteins encoded by mono- and bipartite geminiviruses and the curtovirus C2 can be considered virulence factors, and are known to interact with both basal and inducible systems. This review highlights the role of AC2/C2 in affecting the jasmonic acid and salicylic acid (JA and SA) pathways, the ubiquitin/proteasome system (UPS), and RNA silencing pathways. In addition to suppressing host defenses, AC2/C2 play a critical role in regulating expression of the coat protein during the viral life cycle. It is important that the timing of CP expression is regulated to ensure that ssDNA is converted to dsDNA early during an infection and is sequestered late in the infection. How AC2 interacts with host transcription factors to regulate CP expression is discussed along with how computational approaches can help identify critical host networks targeted by geminivirus AC2 proteins. Thus, the role of AC2/C2 in the viral life-cycle is to prevent the host from mounting an efficient defense response to geminivirus infection and to ensure maximal amplification and encapsidation of the viral genome.
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Affiliation(s)
- Jennifer Guerrero
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, United States
| | - Elizabeth Regedanz
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, Infectious Diseases Institute, The Ohio State University, Columbus, OH, United States
| | - Liu Lu
- Department of Computer Science, North Dakota State University, Fargo, ND, United States
| | - Jianhua Ruan
- Department of Computer Science, University of Texas at San Antonio, San Antonio, TX, United States
| | - David M. Bisaro
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, Infectious Diseases Institute, The Ohio State University, Columbus, OH, United States
| | - Garry Sunter
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, United States
- *Correspondence: Garry Sunter,
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26
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Rishishwar R, Dasgupta I. Suppressors of RNA silencing encoded by geminiviruses and associated DNA satellites. Virusdisease 2019; 30:58-65. [PMID: 31143832 PMCID: PMC6517462 DOI: 10.1007/s13337-018-0418-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 01/05/2018] [Indexed: 12/31/2022] Open
Abstract
In plants, RNA silencing provides a major line of defence against viruses. This antiviral immunity involves production of virus-derived small interfering RNAs (vsiRNAs) and results in specific silencing of viruses by vsiRNAs-guided effector complexes. As a counterattack against RNA silencing, many plant viruses encode suppressors of RNA silencing called viral suppressors of RNA silencing (VSRs), which interfere with the silencing pathway by various mechanisms. This review describes various methods that are being used to characterize viral proteins for suppressor function, VSRs found in geminiviruses and associated DNA satellites and their mechanisms of action.
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Affiliation(s)
- Rashmi Rishishwar
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021 India
| | - Indranil Dasgupta
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021 India
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27
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Hou H, Hu Y, Wang Q, Xu X, Qian Y, Zhou X. Gene Expression Profiling Shows That NbFDN1 Is Involved in Modulating the Hypersensitive Response-Like Cell Death Induced by the Oat dwarf virus RepA Protein. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:1006-1020. [PMID: 29649964 DOI: 10.1094/mpmi-12-17-0291-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this study, we used high-throughput deep nucleotide sequencing to characterize the global transcriptional response of Nicotiana benthamiana plants to transient expression of the RepA protein from Oat dwarf virus (ODV). We identified 7,878 significantly differentially expressed genes (DEG) that mapped to 125 pathways, suggesting that comprehensive networks are involved in regulation of RepA-induced cell death. Of the 202 DEG associated with photosynthesis, expression of 195 was found to be downregulated, indicating a significant inhibition of photosynthesis in response to RepA expression, which is associated with chloroplast disruption and physiological changes. We focused our analysis on NbFDN1, a member of the ferredoxin protein family that participates in the chloroplast electron transport chain performing oxygenic photosynthesis, which was identified to directly interact with NbTsip1. We separately knocked down the expression of NbFDN1 and NbTsip1 using virus-induced gene silencing, and found that NbFDN1 silencing speeded up the development of RepA-induced cell death, unlike NbTsip1 silencing, which showed an opposite effect on RepA-induced response. Further study showed increased H2O2 accumulation and a negative correlation between the transcripts of NbFDN1 and NbTsip1 in NbFDN1-silenced plants. Hence, we speculate that NbFDN1 has an effect on RepA-induced hypersensitive response-like response by modulating NbTsip1 transcription as well as H2O2 production.
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Affiliation(s)
- Huwei Hou
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, People's Republic of China; and
| | - Ya Hu
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, People's Republic of China; and
| | - Qian Wang
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, People's Republic of China; and
| | - Xiongbiao Xu
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, People's Republic of China; and
| | - Yajuan Qian
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, People's Republic of China; and
| | - Xueping Zhou
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, People's Republic of China; and
- 2 State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China
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28
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Functional Scanning of Apple Geminivirus Proteins as Symptom Determinants and Suppressors of Posttranscriptional Gene Silencing. Viruses 2018; 10:v10090488. [PMID: 30208627 PMCID: PMC6164617 DOI: 10.3390/v10090488] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/26/2018] [Accepted: 09/07/2018] [Indexed: 12/21/2022] Open
Abstract
Apple geminivirus (AGV) is a recently identified geminivirus which is isolated from the apple tree in China. We carried out functional scanning of apple geminivirus proteins as symptom determinants and suppressors of posttranscriptional gene silencing (PTGS). Our results indicated that AGV V2 is an important virulence factor localized to the nucleus and cytoplasm that suppresses PTGS and induces severe symptoms of crinkling and necrosis. AGV C1 is also a virulence determinant which elicits systemic necrosis when expressed from a PVX-based vector. The AGV C4 is targeted to cytoplasm, plasma membrane, nucleus, and chloroplasts. The inoculation of PVX-C4 on N. benthamiana induced severe upward leaf curling, which implied that AGV C4 also functions as a symptom determinant, and mutation analyses suggested that the acylated residues on Gly2 and Cys8 play important roles in its subcellular localization and symptom development.
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29
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Yang X, Ren Y, Sun S, Wang D, Zhang F, Li D, Li S, Zhou X. Identification of the Potential Virulence Factors and RNA Silencing Suppressors of Mulberry Mosaic Dwarf-Associated Geminivirus. Viruses 2018; 10:E472. [PMID: 30177616 PMCID: PMC6163789 DOI: 10.3390/v10090472] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/27/2018] [Accepted: 08/30/2018] [Indexed: 01/31/2023] Open
Abstract
Plant viruses encode virulence factors or RNA silencing suppressors to reprogram plant cellular processes or to fine-tune host RNA silencing-mediated defense responses. In a previous study, Mulberry mosaic dwarf-associated virus (MMDaV), a novel, highly divergent geminivirus, has been identified from a Chinese mulberry tree showing mosaic and dwarfing symptoms, but the functions of its encoded proteins are unknown. In this study, all seven proteins encoded by MMDaV were screened for potential virulence and RNA silencing suppressor activities. We found that V2, RepA, and Rep affect the pathogenicity of a heterologous potato virus X. We showed that V2 could inhibit local RNA silencing and long-distance movement of the RNA silencing signal, but not short-range spread of the green fluorescent protein (GFP) silencing signal in Nicotiana benthamiana 16c plants. In addition, V2 localized to both subnuclear foci and the cytoplasm. Deletion mutagenesis of V2 showed that the basic motif from amino acids 61 to 76 was crucial for V2 to form subnuclear foci and for suppression of RNA silencing. Although the V2 protein encoded by begomoviruses or a curtovirus has been shown to have silencing suppressor activity, this is the first identification of an RNA silencing suppressor from a woody plant-infecting geminivirus.
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Affiliation(s)
- Xiuling Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Yanxiang Ren
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
| | - Shaoshuang Sun
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Dongxue Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Fanfan Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Dawei Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
| | - Shifang Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Xueping Zhou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, Zhejiang, China.
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Saeed F, Sattar MN, Hameed U, Ilyas M, Haider MS, Hamza M, Mansoor S, Amin I. Infectivity of okra enation leaf curl virus and the role of its V2 protein in pathogenicity. Virus Res 2018; 255:90-94. [PMID: 30009848 DOI: 10.1016/j.virusres.2018.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 07/10/2018] [Accepted: 07/12/2018] [Indexed: 11/16/2022]
Abstract
Cotton crop has been severely affected by multiple begomoviruses in Pakistan and India. In our previous study, we found okra enation leaf curl virus (OELCuV), cotton leaf curl Multan betasatellite (CLCuMuB) and cotton leaf curl Multan alphasatellite (CLCuMuA) infecting cotton in Pakistan. The current study was designed to investigate the infectivity of OELCuV and its ability to trans-replicate non-cognate CLCuMuB. Agro-infectious clones containing the partial tandem repeats of OELCuV and CLCuMuB were constructed and the infectivity assays were carried out through Agrobacterium mediated transformation in the model host species Nicotiana benthamiana under controlled conditions. The results showed that in the inoculated plants OELCuV alone can cause downward curling and yellowing of leaves with thickened veins. However, when co-inoculated with the non-cognate CLCuMuB it could functionally trans-replicate CLCuMuB resulting in a more severe phenotype. The expression of Pre-coat/V2 protein in the N. benthamiana plants through the potato virus X (PVX) system caused localized cell death after severe leaf curling in the infiltrated leaves. The tissue tropism of the virus was associated with the systemic development of a hypersensitive response (HR), which ultimately lead to the plant death. The results indicated the involvement of V2 protein in the pathogenicity of OELCuV and its ability to trigger the host defense machinery. This study also demonstrated the ability of OELCuV to trans-replicate CLCuMuB resulting in typical leaf curl disease symptoms in N. benthamiana.
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Affiliation(s)
- Farah Saeed
- Institute of Agricultural Sciences, Box 540000, University of the Punjab, Lahore, Pakistan
| | | | - Usman Hameed
- Institute of Agricultural Sciences, Box 540000, University of the Punjab, Lahore, Pakistan
| | - Muhammad Ilyas
- School of Plant Sciences, Box 85721, University of Arizona, Tucson, USA
| | - Muhammad Saleem Haider
- Institute of Agricultural Sciences, Box 540000, University of the Punjab, Lahore, Pakistan
| | - Muhammad Hamza
- National Institute for Biotechnology and Genetic Engineering (NIBGE), Box 577, Faisalabad, Pakistan
| | - Shahid Mansoor
- National Institute for Biotechnology and Genetic Engineering (NIBGE), Box 577, Faisalabad, Pakistan
| | - Imran Amin
- National Institute for Biotechnology and Genetic Engineering (NIBGE), Box 577, Faisalabad, Pakistan.
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31
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Basu S, Kumar Kushwaha N, Kumar Singh A, Pankaj Sahu P, Vinoth Kumar R, Chakraborty S. Dynamics of a geminivirus-encoded pre-coat protein and host RNA-dependent RNA polymerase 1 in regulating symptom recovery in tobacco. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2085-2102. [PMID: 29432546 PMCID: PMC6019014 DOI: 10.1093/jxb/ery043] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 01/24/2018] [Indexed: 05/21/2023]
Abstract
RNA silencing is an integral part of the cellular defense mechanisms in plants that act against virus infection. However, the specific role of RNA silencing and the interplay between host and virus components during recovery from geminivirus infection remains unknown. Hence, in this study we aimed to examine the mechanism behind the host-specific recovery of Nicotiana tabacum infected with Tomato leaf curl Gujarat virus (ToLCGV). Unlike Tomato leaf curl New Delhi virus (ToLCNDV), ToLCGV infection resulted in symptom remission in N. tabacum, and we found that this was mainly due to cross-talk between the pre-coat protein (encoded by the AV2 ORF) of the virus and the host RNA-silencing component RNA-dependent RNA polymerase 1 (encoded by NtRDR1) of N. tabacum. Moreover, apart from the AV2 mutant, other mutants of ToLCNDV developed severe symptoms on a transgenic NtRDR1-overexpression line of N. benthamiana. In contrast, inoculation with ToLCGV resulted in symptom remission, which was due to enhanced methylation of the ToLCGV promoter. Our study reveals a novel 'arms race' in which the pre-coat protein of ToLCNDV selectively blocks the recovery process through inhibiting host-specific RDR1-mediated antiviral silencing in tobacco.
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Affiliation(s)
- Saumik Basu
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Nirbhay Kumar Kushwaha
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Ashish Kumar Singh
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Pranav Pankaj Sahu
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - R Vinoth Kumar
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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Single amino acid in V2 encoded by TYLCV is responsible for its self-interaction, aggregates and pathogenicity. Sci Rep 2018; 8:3561. [PMID: 29476063 PMCID: PMC5824789 DOI: 10.1038/s41598-018-21446-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 11/20/2017] [Indexed: 11/24/2022] Open
Abstract
The V2 protein encoded by Begomovirus is essential for virus infection and is involved in multiple functions, such as virus movement and suppression of the host defence response. In this study, we reported that V2 encoded by the Tomato yellow leaf curl virus (TYLCV), which is one of the most devastating tomato-infecting begomoviruses, could interact with itself and a S71A mutation of V2 (V2S71A) abolished its self-interaction. Fluorescence results showed that V2 localized primarily in the cytoplasm and around the nucleus. Site-directed mutagenesis V2S71A had the similar subcellular localization, but V2S71A formed fewer large aggregates in the cytoplasm compared to wild-type V2, whereas the level of aggregates came to a similar after treatment with MG132, which indicates that the S71A mutation might affect 26S proteasome-mediated degradation of V2 aggregates. Meanwhile, heterologous expression of V2S71A from a Potato virus X vector induced mild symptoms compared to wild-type V2, delay of virus infection associated with mild symptoms was observed in plants inoculated with TYLCV-S71A, which indicates that the amino acid on position 71 is also involved in the pathogenicity of V2. To the best of our knowledge, this report is the first to state that the S71A mutation of V2 encoded by TYLCV affects the self-interaction, aggregate formation and pathogenicity of V2.
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Roshan P, Kulshreshtha A, Kumar S, Purohit R, Hallan V. AV2 protein of tomato leaf curl Palampur virus promotes systemic necrosis in Nicotiana benthamiana and interacts with host Catalase2. Sci Rep 2018; 8:1273. [PMID: 29352245 PMCID: PMC5775426 DOI: 10.1038/s41598-018-19292-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 12/27/2017] [Indexed: 11/08/2022] Open
Abstract
Tomato leaf curl Palampur virus (ToLCPalV) is a whitefly-transmitted, bipartite begomovirus. Here, we demonstrated that ectopic expression of AV2 from a Potato virus X (PVX)-based vector accelerated systemic necrosis and reactive oxygen species (ROS) accumulation in Nicotiana benthamiana. Furthermore, 10 amino acids from N-terminal region of AV2 were found to be associated with the systemic necrosis symptom/phenotype. Mutational studies of ToLCPalV infectious clones lacking the AV2 revealed that AV2 is essential for the systemic movement of DNA-A, symptom severity and viral DNA accumulation. In a yeast two-hybrid assay, Catalase2 (Cat2) was found to associate with AV2 protein. Further, silencing of Cat2 resulted in appearance of necrotic lesions on N. benthamiana and these plants were highly susceptible to ToLCPalV infection in comparison to control plants. Infection ToLCPalV on Solanum lycopersicum resulted in downregulation of Cat2 transcripts, followed by accumulation of ROS and stress marker transcripts. The AV2 protein also suppressed virus-induced gene silencing (VIGS) of the Phytoene desaturase (PDS) gene. Our results show that AV2 is essential for the pathogenicity, systemic movement and suppression of gene silencing in the host. Altogether, our findings suggest that interactions between AV2 and Cat2 might play a crucial role in the establishment of ToLCPalV infection.
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Affiliation(s)
- Poonam Roshan
- Academy of Scientific & Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, HP, 176061, India
- Plant Virology Lab, CSIR-IHBT, Palampur, HP, 176061, India
| | - Aditya Kulshreshtha
- Academy of Scientific & Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, HP, 176061, India
- Plant Virology Lab, CSIR-IHBT, Palampur, HP, 176061, India
| | - Surender Kumar
- Academy of Scientific & Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, HP, 176061, India
- Plant Virology Lab, CSIR-IHBT, Palampur, HP, 176061, India
| | - Rituraj Purohit
- Academy of Scientific & Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, HP, 176061, India
- Biotechnology division, CSIR-IHBT, Palampur, HP, 176061, India
| | - Vipin Hallan
- Academy of Scientific & Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, HP, 176061, India.
- Plant Virology Lab, CSIR-IHBT, Palampur, HP, 176061, India.
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Roshan P, Kulshreshtha A, Hallan V. Identification of host cellular targets of AC4 and AV2 proteins of tomato leaf curl palampur virus and their sub-cellular localization studies. Virusdisease 2017; 28:390-400. [PMID: 29291230 PMCID: PMC5747847 DOI: 10.1007/s13337-017-0405-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/05/2017] [Indexed: 01/06/2023] Open
Abstract
Tomato leaf curl palampur virus (ToLCPalV) is a bipartite begomovirus with genome organization typical of old world begomoviruses. It infects commercially important crops and weeds in the Asian subcontinent. Apart from other proteins, the DNA-A of the virus encodes AV2 and AC4 proteins of approximately 13.73 and 6.7 kDa, respectively. In case of other begomoviruses, previous studies have shown the role of AV2 and AC4 proteins in virus movement, pathogenesis and suppression of gene silencing. However, the ToLCPalV proteins are significantly variable in comparison to closest relative and hence there is a need to work out their functions. In this study, we identified 9 cellular proteins of tomato that interact with AV2 and AC4 proteins, through yeast two hybrid screening. Upon sequence analysis, these interactors were identified as cysteine protease, katanin p60 ATPase-containing subunit A-like, guanine deaminase, NADH dehydrogenase (ubiquinone) iron-sulfur protein, glyceraldehyde-3-phosphate dehydrogenase B, 60S acidic ribosomal P0 protein, acyl co-A dehydrogenase IBR3, oxygen-evolving enhancer protein 1 and peroxisomal membrane protein 11D. These proteins play a vital role in protein degradation, plant defense response, microtubule severing, photosynthesis and protein synthesis. The two viral proteins, however, did not interact with each other in yeast. AV2 when fused with GFP under the control of cauliflower mosaic virus 35S promoter was localized in nucleus and cytoplasm. On the other hand, AC4-GFP fusion was localized only in cytoplasm. The outcome of present study will help to elucidate the mechanism of viral pathogenesis. Further functional characterization of identified host proteins will provide an insight into their involvement in disease development.
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Affiliation(s)
- Poonam Roshan
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, India
- Plant Virology Lab, Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, HP 176061 India
| | - Aditya Kulshreshtha
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, India
- Plant Virology Lab, Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, HP 176061 India
| | - Vipin Hallan
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, India
- Plant Virology Lab, Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, HP 176061 India
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Luna AP, Rodríguez-Negrete EA, Morilla G, Wang L, Lozano-Durán R, Castillo AG, Bejarano ER. V2 from a curtovirus is a suppressor of post-transcriptional gene silencing. J Gen Virol 2017; 98:2607-2614. [PMID: 28933688 DOI: 10.1099/jgv.0.000933] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The suppression of gene silencing is a key mechanism for the success of viral infection in plants. DNA viruses from the Geminiviridae family encode several proteins that suppress transcriptional and post-transcriptional gene silencing (TGS/PTGS). In Begomovirus, the most abundant genus of this family, three out of six genome-encoded proteins, namely C2, C4 and V2, have been shown to suppress PTGS, with V2 being the strongest PTGS suppressor in transient assays. Beet curly top virus (BCTV), the model species for the Curtovirus genus, is able to infect the widest range of plants among geminiviruses. In this genus, only one protein, C2/L2, has been described as inhibiting PTGS. We show here that, despite the lack of sequence homology with its begomoviral counterpart, BCTV V2 acts as a potent PTGS suppressor, possibly by impairing the RDR6 (RNA-dependent RNA polymerase 6)/suppressor of gene silencing 3 (SGS3) pathway.
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Affiliation(s)
- Ana P Luna
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' (IHSM-UMA-CSIC), Area de Genética, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, E-29071 Málaga, Spain
| | - Edgar A Rodríguez-Negrete
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' (IHSM-UMA-CSIC), Area de Genética, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, E-29071 Málaga, Spain.,Present address: Departamento de Biotecnología Agrícola, Instituto Politécnico Nacional, CIIDIR-IPN, Unidad Sinaloa, Blvd. Juan de Dios Bátiz Paredes No 250. Guasave, Sinaloa CP 81101, Mexico
| | - Gabriel Morilla
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' (IHSM-UMA-CSIC), Area de Genética, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, E-29071 Málaga, Spain
| | - Liping Wang
- Shanghai Center for Plant Stress Biology (PSC), Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, PR China.,University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Rosa Lozano-Durán
- Shanghai Center for Plant Stress Biology (PSC), Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, PR China
| | - Araceli G Castillo
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' (IHSM-UMA-CSIC), Area de Genética, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, E-29071 Málaga, Spain
| | - Eduardo R Bejarano
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' (IHSM-UMA-CSIC), Area de Genética, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, E-29071 Málaga, Spain
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Gorovits R, Moshe A, Amrani L, Kleinberger R, Anfoka G, Czosnek H. The six Tomato yellow leaf curl virus genes expressed individually in tomato induce different levels of plant stress response attenuation. Cell Stress Chaperones 2017; 22:345-355. [PMID: 28324352 PMCID: PMC5425365 DOI: 10.1007/s12192-017-0766-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 01/12/2017] [Accepted: 01/20/2017] [Indexed: 12/20/2022] Open
Abstract
Tomato yellow leaf curl virus (TYLCV) is a begomovirus infecting tomato plants worldwide. TYLCV needs a healthy host environment to ensure a successful infection cycle for long periods. Hence, TYLCV restrains its destructive effect and induces neither a hypersensitive response nor cell death in infected tomatoes. On the contrary, TYLCV counteracts cell death induced by other factors, such as inactivation of HSP90 functionality. Suppression of plant death is associated with the inhibition of the ubiquitin 26S proteasome degradation and with a deactivation of the heat shock transcription factor HSFA2 pathways (including decreased HSP17 levels). The goal of the current study was to find if the individual TYLCV genes were capable of suppressing HSP90-dependent death and HSFA2 deactivation. The expression of C2 (C3 and CP to a lesser extent) caused a decrease in the severity of death phenotypes, while the expression of V2 (C1 and C4 to a lesser extent) strengthened cell death. However, C2 or V2 markedly affected stress response under conditions of viral infection. The downregulation of HSFA2 signaling, initiated by the expression of C1 and V2, was detected in the absence of virus infection, but was enhanced in infected plants, while CP and C4 mitigated HSFA2 levels only in the infected tomatoes. The dependence of analyzed plant stress response suppression on the interaction of the expressed genes with the environment created by the whole virus infection was more pronounced than on the expression of individual TYLCV genes.
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Affiliation(s)
- Rena Gorovits
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel.
| | - Adi Moshe
- Department of Cell Research and Immunology, Tel-Aviv University, 69978, Ramat Aviv, Israel
| | - Linoy Amrani
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel
| | - Rotem Kleinberger
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel
| | - Ghandi Anfoka
- Faculty of Agricultural Technology, Department of Biotechnology, Al-Balqa' Applied University, Al-Salt, 19117, Jordan
| | - Henryk Czosnek
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel
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Wang L, Tan H, Wu M, Jimenez-Gongora T, Tan L, Lozano-Duran R. Dynamic Virus-Dependent Subnuclear Localization of the Capsid Protein from a Geminivirus. FRONTIERS IN PLANT SCIENCE 2017; 8:2165. [PMID: 29312406 PMCID: PMC5744400 DOI: 10.3389/fpls.2017.02165] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 12/08/2017] [Indexed: 05/13/2023]
Abstract
Viruses are intracellular parasites with a nucleic acid genome and a proteinaceous capsid. Viral capsids are formed of at least one virus-encoded capsid protein (CP), which is often multifunctional, playing additional non-structural roles during the infection cycle. In animal viruses, there are examples of differential localization of CPs associated to the progression of the infection and/or enabled by other viral proteins; these changes in the distribution of CPs may ultimately regulate the involvement of these proteins in different viral functions. In this work, we analyze the subcellular localization of a GFP- or RFP-fused CP from the plant virus Tomato yellow leaf curl virus (TYLCV; Fam. Geminiviridae) in the presence or absence of the virus upon transient expression in the host plants Nicotiana benthamiana and tomato. Our findings show that, in agreement with previous reports, when the CP is expressed alone it localizes mainly in the nucleolus and weakly in the nucleoplasm. Interestingly, the presence of the virus causes the sequential re-localization of the CP outside of the nucleolus and into discrete nuclear foci and, eventually, into an uneven distribution in the nucleoplasm. Expression of the viral replication-associated protein, Rep, is sufficient to exclude the CP from the nucleolus, but the localization of the CP in the characteristic patterns induced by the virus cannot be recapitulated by co-expression with any individual viral protein. Our results demonstrate that the subcellular distribution of the CP is a dynamic process, temporally regulated throughout the progression of the infection. The regulation of the localization of the CP is determined by the presence of other viral components or changes in the cellular environment induced by the virus, and is likely to contribute to the multifunctionality of this protein. Bearing in mind these observations, we suggest that viral proteins should be studied in the context of the infection and considering the temporal dimension in order to comprehensively understand their roles and effects in the interaction between virus and host.
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Affiliation(s)
- Liping Wang
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Huang Tan
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Mengshi Wu
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Tamara Jimenez-Gongora
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Li Tan
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
| | - Rosa Lozano-Duran
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
- *Correspondence: Rosa Lozano-Duran,
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Qian Y, Hou H, Shen Q, Cai X, Sunter G, Zhou X. RepA Protein Encoded by Oat dwarf virus Elicits a Temperature-Sensitive Hypersensitive Response-Type Cell Death That Involves Jasmonic Acid-Dependent Signaling. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:5-21. [PMID: 26720685 DOI: 10.1094/mpmi-07-15-0149-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The hypersensitive response (HR) is a component of disease resistance that is often induced by pathogen infection, but essentially no information is available for members of the destructive mastreviruses. We have investigated an HR-type response elicited in Nicotiana species by Oat dwarf virus (ODV) and have found that expression of the ODV RepA protein but not other ODV-encoded proteins elicits the HR-type cell death associated with a burst of H2O2. Deletion mutagenesis indicates that the first nine amino acids (aa) at the N terminus of RepA and the two regions located between aa residues 173 and 195 and between aa residues 241 and 260 near the C terminus are essential for HR-type cell-death elicitation. Confocal and electron microscopy showed that the RepA protein is localized in the nuclei of plant cells and might contain bipartite nuclear localization signals. The HR-like lesions mediated by RepA were inhibited by temperatures above 30°C and involvement of jasmonic acid (JA) in HR was identified by gain- and loss-of-function experiments. To our knowledge, this is the first report of an elicitor of HR-type cell death from mastreviruses.
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Affiliation(s)
- Yajuan Qian
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310029, People's Republic of China
| | - Huwei Hou
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310029, People's Republic of China
- 2 State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, People's Republic of China
| | - Qingtang Shen
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310029, People's Republic of China
| | - Xinzhong Cai
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310029, People's Republic of China
| | - Garry Sunter
- 3 Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, U.S.A
| | - Xueping Zhou
- 1 State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310029, People's Republic of China
- 2 State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, People's Republic of China
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Li F, Xu X, Huang C, Gu Z, Cao L, Hu T, Ding M, Li Z, Zhou X. The AC5 protein encoded by Mungbean yellow mosaic India virus is a pathogenicity determinant that suppresses RNA silencing-based antiviral defenses. THE NEW PHYTOLOGIST 2015; 208:555-69. [PMID: 26010321 DOI: 10.1111/nph.13473] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 04/16/2015] [Indexed: 06/04/2023]
Abstract
It is generally accepted that begomoviruses in the family Geminiviridae encode four proteins (from AC1/C1 to AC4/C4) using the complementary-sense DNA as template. Although AC5/C5 coding sequences are increasingly annotated in databases for many begomoviruses, the evolutionary relationships and functions of this putative protein in viral infection are obscure. Here, we demonstrate several important functions of the AC5 protein of a bipartite begomovirus, Mungbean yellow mosaic India virus (MYMIV). Mutational analyses and transgenic expression showed that AC5 plays a critical role in MYMIV infection. Ectopic expression of AC5 from a Potato virus X (PVX) vector resulted in severe mosaic symptoms followed by a hypersensitive-like response in Nicotiana benthamiana. Furthermore, MYMIV AC5 effectively suppressed post-transcriptional gene silencing induced by single-stranded but not double-stranded RNA. AC5 was also able to reverse transcriptional gene silencing of a green fluorescent protein transgene by reducing methylation of promoter sequences, probably through repressing expression of a CHH cytosine methyltransferase (DOMAINS REARRANGED METHYLTRANSFERASE2) in N. benthamiana. Our results demonstrate that MYMIV AC5 is a pathogenicity determinant and a potent RNA silencing suppressor that employs novel mechanisms to suppress antiviral defenses, and suggest that the AC5 function may be conserved among many begomoviruses.
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Affiliation(s)
- Fangfang Li
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Xiongbiao Xu
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Changjun Huang
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Zhouhang Gu
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Linge Cao
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Tao Hu
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Ming Ding
- Institute of Plant Protection, Yunnan Provincial Academy of Agricultural Sciences, Kunming, Yunnan, 650205, China
| | - Zhenghe Li
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
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Singh A, Taneja J, Dasgupta I, Mukherjee SK. Development of plants resistant to tomato geminiviruses using artificial trans-acting small interfering RNA. MOLECULAR PLANT PATHOLOGY 2015; 16:724-34. [PMID: 25512230 PMCID: PMC6638473 DOI: 10.1111/mpp.12229] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
RNA interference (RNAi), a conserved RNA-mediated gene regulatory mechanism in eukaryotes, plays an important role in plant growth and development, and as an antiviral defence system in plants. As a counter-strategy, plant viruses encode RNAi suppressors to suppress the RNAi pathways and consequently down-regulate plant defence. In geminiviruses, the proteins AC2, AC4 and AV2 are known to act as RNAi suppressors. In this study, we have designed a gene silencing vector using the features of trans-acting small interfering RNA (tasiRNA), which is simple and can be used to target multiple genes at a time employing a single-step cloning procedure. This vector was used to target two RNAi suppressor proteins (AC2 and AC4) of the geminivirus, Tomato leaf curl New Delhi virus (ToLCNDV). The vector containing fragments of ToLCNDV AC2 and AC4 genes, on agro-infiltration, produced copious quantities of AC2 and AC4 specific siRNA in both tobacco and tomato plants. On challenge inoculation of the agro-infiltrated plants with ToLCNDV, most plants showed an absence of symptoms and low accumulation of viral DNA. Transgenic tobacco plants were raised using the AC2 and AC4 tasiRNA-generating constructs, and T1 plants, obtained from the primary transgenic plants, were tested for resistance separately against ToLCNDV and Tomato leaf curl Gujarat virus. Most plants showed an absence of symptoms and low accumulation of the corresponding viruses, the resistance being generally proportional to the amounts of siRNA produced against AC2 and AC4 genes. This is the first report of the use of artificial tasiRNA to generate resistance against an important plant virus.
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Affiliation(s)
- Archana Singh
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Jyoti Taneja
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Indranil Dasgupta
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Sunil Kumar Mukherjee
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
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Csorba T, Kontra L, Burgyán J. viral silencing suppressors: Tools forged to fine-tune host-pathogen coexistence. Virology 2015; 479-480:85-103. [DOI: 10.1016/j.virol.2015.02.028] [Citation(s) in RCA: 368] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 01/31/2015] [Accepted: 02/16/2015] [Indexed: 12/27/2022]
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Ammara UE, Mansoor S, Saeed M, Amin I, Briddon RW, Al-Sadi AM. RNA interference-based resistance in transgenic tomato plants against Tomato yellow leaf curl virus-Oman (TYLCV-OM) and its associated betasatellite. Virol J 2015; 12:38. [PMID: 25890080 PMCID: PMC4359554 DOI: 10.1186/s12985-015-0263-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 02/10/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Tomato yellow leaf curl virus (TYLCV), a monopartite begomovirus (family Geminiviridae) is responsible for heavy yield losses for tomato production around the globe. In Oman at least five distinct begomoviruses cause disease in tomato, including TYLCV. Unusually, TYLCV infections in Oman are sometimes associated with a betasatellite (Tomato leaf curl betasatellite [ToLCB]; a symptom modulating satellite). RNA interference (RNAi) can be used to develop resistance against begomoviruses at either the transcriptional or post-transcriptional levels. RESULTS A hairpin RNAi (hpRNAi) construct to express double-stranded RNA homologous to sequences of the intergenic region, coat protein gene, V2 gene and replication-associated gene of Tomato yellow leaf curl virus-Oman (TYLCV-OM) was produced. Initially, transient expression of the hpRNAi construct at the site of virus inoculation was shown to reduce the number of plants developing symptoms when inoculated with either TYLCV-OM or TYLCV-OM with ToLCB-OM to Nicotiana benthamiana or tomato. Solanum lycopersicum L. cv. Pusa Ruby was transformed with the hpRNAi construct and nine confirmed transgenic lines were obtained and challenged with TYLCV-OM and ToLCB-OM by Agrobacterium-mediated inoculation. For all but one line, for which all plants remained symptomless, inoculation with TYLCV-OM led to a proportion (≤25%) of tomato plants developing symptoms of infection. For inoculation with TYLCV-OM and ToLCB-OM all lines showed a proportion of plants (≤45%) symptomatic. However, for all infected transgenic plants the symptoms were milder and virus titre in plants was lower than in infected non-transgenic tomato plants. CONCLUSIONS These results show that RNAi can be used to develop resistance against geminiviruses in tomato. The resistance in this case is not immunity but does reduce the severity of infections and virus titer. Also, the betasatellite may compromise resistance, increasing the proportion of plants which ultimately show symptoms.
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Affiliation(s)
- Um e Ammara
- Department of Crop Sciences, College of Agriculture and Marine Sciences, Sultan Qaboos University, P.O. Box-34, 123, Al-Khod, Oman.
| | - Shahid Mansoor
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan.
| | - Muhammad Saeed
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan.
| | - Imran Amin
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan.
| | - Rob W Briddon
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan.
| | - Abdullah Mohammed Al-Sadi
- Department of Crop Sciences, College of Agriculture and Marine Sciences, Sultan Qaboos University, P.O. Box-34, 123, Al-Khod, Oman.
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Hak H, Levy Y, Chandran SA, Belausov E, Loyter A, Lapidot M, Gafni Y. TYLCV-Is movement in planta does not require V2 protein. Virology 2015; 477:56-60. [PMID: 25644513 DOI: 10.1016/j.virol.2015.01.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 12/21/2014] [Accepted: 01/05/2015] [Indexed: 11/30/2022]
Abstract
Tomato yellow leaf curl virus (TYLCV), a major tomato pathogen causing extensive crop losses, is a whitefly-transmitted geminivirus. V2 mutants of TYLCV-Is and related viruses tend to induce symptomless infection with attenuated viral DNA levels, while accumulating close to wild-type DNA levels in protoplasts, suggesting V2 as a movement protein. The discovery of plant-silencing mechanisms and viral silencing suppressors, V2 included, led us to reconsider V2׳s involvement in viral movement. We studied two mutant versions of the virus, one impaired in V2 silencing-suppression activity, and another carrying a non-translatable V2. While both mutant viruses spread in the infected plant to newly emerged leaves at the same rate as the wild-type virus, their DNA-accumulation levels were tenfold lower than in the wild-type virus. Thus, we suggest that the setback in virus proliferation, previously ascribed to a movement impediment, is due to lack of silencing-suppression activity.
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Affiliation(s)
- Hagit Hak
- Institute of Plant Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel; Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Yael Levy
- Institute of Plant Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
| | - Sam A Chandran
- Institute of Plant Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
| | - Eduard Belausov
- Institute of Plant Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
| | - Abraham Loyter
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Moshe Lapidot
- Institute of Plant Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
| | - Yedidya Gafni
- Institute of Plant Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel.
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Wang Y, Dang M, Hou H, Mei Y, Qian Y, Zhou X. Identification of an RNA silencing suppressor encoded by a mastrevirus. J Gen Virol 2014; 95:2082-2088. [PMID: 24866851 DOI: 10.1099/vir.0.064246-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Wheat dwarf virus (WDV) is a DNA virus belonging to the genus Mastrevirus of the family Geminiviridae. In this study, we report that the Rep protein encoded by WDV is a RNA silencing supressor as determined by co-infiltration assays using transgenic Nicotiana benthamiana line 16c carrying the GFP reporter gene. The Rep protein was shown to inhibit both local and systemic RNA silencing of the GFP gene as well as the spread of systemic GFP RNA silencing signals. Gel mobility shift assays showed that the Rep protein binds 21 nt and 24 nt small interfering RNA (siRNA) duplexes and single-stranded (ss)-siRNA. To our knowledge, this is the first identification of an RNA silencing suppressor encoded by mastreviruses. Furthermore, deletion mutagenesis indicates that both the N- and C-terminal regions of the Rep protein are not critical for silencing suppression and self-interaction, but the N terminus of Rep is necessary for its pathogenicity.
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Affiliation(s)
- Yaqin Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, PR China
| | - Mingqing Dang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, PR China
| | - Huwei Hou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, PR China
| | - Yuzhen Mei
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, PR China
| | - Yajuan Qian
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, PR China
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, PR China
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45
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de Ronde D, Butterbach P, Kormelink R. Dominant resistance against plant viruses. FRONTIERS IN PLANT SCIENCE 2014; 5:307. [PMID: 25018765 PMCID: PMC4073217 DOI: 10.3389/fpls.2014.00307] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Accepted: 06/10/2014] [Indexed: 05/17/2023]
Abstract
To establish a successful infection plant viruses have to overcome a defense system composed of several layers. This review will overview the various strategies plants employ to combat viral infections with main emphasis on the current status of single dominant resistance (R) genes identified against plant viruses and the corresponding avirulence (Avr) genes identified so far. The most common models to explain the mode of action of dominant R genes will be presented. Finally, in brief the hypersensitive response (HR) and extreme resistance (ER), and the functional and structural similarity of R genes to sensors of innate immunity in mammalian cell systems will be described.
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Affiliation(s)
- Dryas de Ronde
- Laboratory of Virology, Department of Plant Sciences, Wageningen University Wageningen, Netherlands
| | - Patrick Butterbach
- Laboratory of Virology, Department of Plant Sciences, Wageningen University Wageningen, Netherlands
| | - Richard Kormelink
- Laboratory of Virology, Department of Plant Sciences, Wageningen University Wageningen, Netherlands
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Abstract
Geminiviruses are a family of plant viruses that cause economically important plant diseases worldwide. These viruses have circular single-stranded DNA genomes and four to eight genes that are expressed from both strands of the double-stranded DNA replicative intermediate. The transcription of these genes occurs under the control of two bidirectional promoters and one monodirectional promoter. The viral proteins function to facilitate virus replication, virus movement, the assembly of virus-specific nucleoprotein particles, vector transmission and to counteract plant host defence responses. Recent research findings have provided new insights into the structure and function of these proteins and have identified numerous host interacting partners. Most of the viral proteins have been shown to be multifunctional, participating in multiple events during the infection cycle and have, indeed, evolved coordinated interactions with host proteins to ensure a successful infection. Here, an up-to-date review of viral protein structure and function is presented, and some areas requiring further research are identified.
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Affiliation(s)
- Vincent N Fondong
- Department of Biological Sciences, Delaware State University, 1200 North DuPont Highway, Dover, DE 19901, USA.
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Vu TV, Roy Choudhury N, Mukherjee SK. Transgenic tomato plants expressing artificial microRNAs for silencing the pre-coat and coat proteins of a begomovirus, Tomato leaf curl New Delhi virus, show tolerance to virus infection. Virus Res 2013; 172:35-45. [DOI: 10.1016/j.virusres.2012.12.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 12/18/2012] [Accepted: 12/19/2012] [Indexed: 10/27/2022]
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Luna AP, Morilla G, Voinnet O, Bejarano ER. Functional analysis of gene-silencing suppressors from tomato yellow leaf curl disease viruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:1294-306. [PMID: 22712505 DOI: 10.1094/mpmi-04-12-0094-r] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Tomato yellow leaf curl disease (TYLCD) is caused by a complex of phylogenetically related Begomovirus spp. that produce similar symptoms when they infect tomato plants but have different host ranges. In this work, we have evaluated the gene-silencing-suppression activity of C2, C4, and V2 viral proteins isolated from the four main TYLCD-causing strains in Spain in Nicotiana benthamiana. We observed varying degrees of local silencing suppression for each viral protein tested, with V2 proteins from all four viruses exhibiting the strongest suppression activity. None of the suppressors were able to avoid the spread of the systemic silencing, although most produced a delay. In order to test the silencing-suppression activity of Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Sardinia virus (TYLCSV) proteins in a shared (tomato) and nonshared (bean) host, we established novel patch assays. Using these tools, we found that viral proteins from TYLCV were able to suppress silencing in both hosts, whereas TYLCSV proteins were only effective in tomato. This is the first time that viral suppressors from a complex of disease-causing geminiviruses have been subject to a comprehensive analysis using two economically important crop hosts, as well as the established N. benthamiana plant model.
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Affiliation(s)
- Ana P Luna
- Departamento de Genetica, Universidad de Malaga, Malaga, Spain
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Zhang J, Dong J, Xu Y, Wu J. V2 protein encoded by Tomato yellow leaf curl China virus is an RNA silencing suppressor. Virus Res 2012; 163:51-8. [PMID: 21893116 DOI: 10.1016/j.virusres.2011.08.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Revised: 08/16/2011] [Accepted: 08/18/2011] [Indexed: 11/30/2022]
Abstract
The V2 protein of Tomato yellow leaf curl China virus (TYLCCNV) was identified as an RNA silencing suppressor by Agrobacterium-mediated co-infiltration. The V2 protein could inhibit local RNA silencing, systemic RNA silencing of the green fluorescent protein (GFP) gene and the spread of a systemic GFP RNA silencing signal. However, the V2 could not interfere with the cell-to-cell spread of RNA silencing. Subcellular localization assay indicated that the V2 protein was distributed in the cytoplasm of Nicotiana benthamiana cells, and accumulated in irregular cytoplasmic bodies. The V2 bound 21nt and 24nt small interfering RNA (siRNA) duplexes and 24nt single-stranded (ss)-siRNA but not 21nt ss-siRNA in electrophoresis mobility shift assays. Expression of the V2 protein via the Potato virus X (PVX) vectors heterogenous system induced severe symptoms in N. benthamiana. In a yeast two-hybrid system, TYLCCNV V2 could interact with itself, but not with SlSGS3, which is known to been involved in RNA silencing pathway and to interact with a closely related Tomato yellow leaf curl virus (TYLCV) V2. These results indicate that TYLCCNV V2 is an RNA silencing suppressor, possibly through sequestering siRNA molecules.
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Affiliation(s)
- Jie Zhang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310029, PR China
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Poornima Priyadarshini CG, Ambika MV, Tippeswamy R, Savithri HS. Functional characterization of coat protein and V2 involved in cell to cell movement of Cotton leaf curl Kokhran virus-Dabawali. PLoS One 2011; 6:e26929. [PMID: 22110597 PMCID: PMC3217939 DOI: 10.1371/journal.pone.0026929] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 10/06/2011] [Indexed: 02/06/2023] Open
Abstract
The functional attributes of coat protein (CP) and V2 of the monopartite begomovirus, Cotton leaf curl Kokhran virus- Dabawali were analyzed in vitro and in vivo by their overexpression in E. coli, insect cells and transient expression in the plant system. Purified recombinant V2 and CP proteins were shown to interact with each other using ELISA and surface plasmon resonance. Confocal microscopy of Sf21 cells expressing V2 and CP proteins revealed that V2 localized to the cell periphery and CP to the nucleus. Deletion of the N terminal nuclear localization signal of CP restricted its distribution to the cytoplasm. GFP-V2 and YFP-CP transiently expressed in N. benthamiana plants by agroinfiltration substantiated the localization of V2 to the cell periphery and CP predominantly to the nucleus. Interestingly, upon coinfiltration, CP was found both in the nucleus and in the cytoplasm along with V2. These results suggest that the interaction of V2 and CP may have important implications in the cell to cell movement.
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Affiliation(s)
| | - M. V. Ambika
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - R. Tippeswamy
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - H. S. Savithri
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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