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Chen Y, Guo S, Jiang L, Yan F, Hao K, Wang Z, An M, Xia Z, Li F, Zhou X, Wu Y. Molecular characterization and pathogenicity of a novel monopartite geminivirus infecting tobacco in China. Virology 2024; 594:110061. [PMID: 38518441 DOI: 10.1016/j.virol.2024.110061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/11/2024] [Accepted: 03/14/2024] [Indexed: 03/24/2024]
Abstract
The occurrence of geminiviruses causes significant economic losses in many economically important crops. In this study, a novel geminivirus isolated from tobacco in Sichuan province of China, named tomato leaf curl Chuxiong virus (TLCCxV), was characterized by small RNA-based deep sequencing. The full-length of TLCCxV genome was determined to be 2744 nucleotides (nt) encoding six open reading frames. Phylogenetic and genome-wide pairwise identity analysis revealed that TLCCxV shared less than 91% identities with reported geminiviruses. A TLCCxV infectious clone was constructed and successfully infected Nicotiana benthamiana, N. tabacum, N. glutinosa, Solanum lycopersicum and Petunia hybrida plants. Furthermore, expression of the V2, C1 and C4 proteins through a potato virus X vector caused severe chlorosis or necrosis symptom in N. benthamiana. Taken together, we identified a new geminivirus in tobacco plants, and found that V2, C1 and C4 contribute to symptom development.
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Affiliation(s)
- Yuan Chen
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866, China
| | - Shiping Guo
- Sichuan Tobacco Company, Chengdu, Sichuan, 610000, China
| | - Lianqiang Jiang
- Liangshan Branch of Sichuan Tobacco Company, Xichang, Sichuan, 615000, China
| | - Fangfang Yan
- Panzhihua Branch of Sichuan Tobacco Company, Panzhihua, Sichuan, 617000, China
| | - Kaiqiang Hao
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866, China
| | - Zhiping Wang
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866, China
| | - Mengnan An
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866, China
| | - Zihao Xia
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866, China
| | - Fangfang 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
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866, China; 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, Zhejiang, 310058, China.
| | - Yuanhua Wu
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866, China.
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Ye X, Ding D, Chen Y, Liu C, Li Z, Lou B, Zhou Y. Identification of RNA silencing suppressor encoded by citrus chlorotic dwarf-associated virus. Front Microbiol 2024; 15:1328289. [PMID: 38333582 PMCID: PMC10850569 DOI: 10.3389/fmicb.2024.1328289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 01/04/2024] [Indexed: 02/10/2024] Open
Abstract
Introduction Citrus chlorotic dwarf-associated virus (CCDaV) is an economically important citrus virus associated with leaf curling, deformation, and chlorosis found in China. Plants have evolved RNA silencing to defend against viral infections; however, the mechanism by which CCDaV suppresses RNA silencing in citrus remains unknown. Methods Six proteins encoded by CCDaV were ectopically expressed in Nicotiana benthamiana 16c using the pCHF3 vector to identify RNA-silencing suppression activities. Results V2 protein encoded by CCDaV suppressed local RNA silencing and systemic RNA silencing triggered by GFP RNA, but did not impede short-distance movement of the RNA silencing signal in N. benthamiana 16c. GFP fluorescence observations showed that the ability of V2 protein to suppress RNA silencing was weaker than tomato bushy stunt virus P19. Deletion analysis showed that the putative nuclear localization signal (NLS, 25-54 aa) was involved in the RNA silencing suppression activity of V2 protein. Furthermore, V2 protein cannot block dsRNA-triggered RNA silencing. The subcellular localization assay suggested that V2 protein was localized to nucleus of N. benthamiana. Conclusion Overall, the results of this study demonstrate that CCDaV-V2 acts as an activity of silencing suppression. This is the first reported RNA-silencing suppressor encoded by Citlodavirus and will be valuable in revealing the molecular mechanism of CCDaV infection.
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Affiliation(s)
- Xiao Ye
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City/Citrus Research Institute, Southwest University, Chongqing, China
| | - Dongdong Ding
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City/Citrus Research Institute, Southwest University, Chongqing, China
| | - Yuan Chen
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City/Citrus Research Institute, Southwest University, Chongqing, China
| | - Chuang Liu
- Lemon Industry Development Center, Anyue, Sichuan, China
| | - Zhongan Li
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City/Citrus Research Institute, Southwest University, Chongqing, China
| | - Binghai Lou
- Guangxi Citrus Breeding and Cultivation Research Center of Engineering Technology/Guangxi Academy of Specialty Crops, Guilin, Guangxi, China
| | - Yan Zhou
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City/Citrus Research Institute, Southwest University, Chongqing, China
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Han TT, Tang JX, Fang M, Zhang P, Han PY, Yin ZN, Ma Y, Zhang J, Lu QY. Two genes encoded by mulberry crinkle leaf virus (MCLV): The V4 gene enhances viral replication, and the V5 gene is needed for MCLV infection in Nicotiana benthamiana. Virus Res 2024; 339:199288. [PMID: 38043724 PMCID: PMC10751690 DOI: 10.1016/j.virusres.2023.199288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 11/21/2023] [Accepted: 11/26/2023] [Indexed: 12/05/2023]
Abstract
Mulberry crinkle leaf virus (MCLV) is a member of the genus Mulcrilevirus, family Geminiviridae. The expression and functions of the V4 and V5 genes encoded by the MCLV genome remain unknown. Here, we confirmed the expression of V4 and V5 by analyzing the V4 and V5 mRNAs and the promoter activity of individual ORFs upstream sequences. The functions of V4 and V5 were investigated by constructing Agrobacterium-mediated infectious clones of wild-type MCLV variant П (MCLV vII), MCLVwt and MCLV vП mutants, such as MCLVmV4 (start codon of V4 ORF mutated), MCLVdV4 (5'-end partial deletion of V4 ORF sequence) and MCLVmV5 (V5 ORF start codon mutated). Although MCLVwt, MCLVmV4, and MCLVdV4 could infect natural host mulberry and experimental tomato plants systematically, the replication of the MCLVmV4 and MCLVdV4 genomes was obviously reduced compared to MCLVwt in both mulberry and tomato plants. MCLV vП expressing V5 could infect Nicotiana benthamiana plants systematically, but MCLVmV5 could not, implying that V5 is needed for MCLV vП to infect N. benthamiana plants. Taken together, V4 is involved in replication of the MCLV genome in host plants, and V5 potentially might extend the host range. Our findings lay a foundation for in-depth insight into the functions of MCLV-encoded proteins and provide a novel perspective for the subsequent study of MCLV-host plant interactions.
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Affiliation(s)
- Tao-Tao Han
- College of Biotechnology, Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China
| | - Jia-Xuan Tang
- College of Biotechnology, Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China
| | - Miao Fang
- College of Biotechnology, Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China
| | - Peng Zhang
- College of Biotechnology, Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China
| | - Pei-Yu Han
- College of Biotechnology, Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China
| | - Zhen-Ni Yin
- College of Biotechnology, Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China
| | - Yu Ma
- College of Biotechnology, Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China
| | - Jian Zhang
- College of Biotechnology, Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China; Key Laboratory of Genetic Improvement of Silkworm and Mulberry, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu 212100, China
| | - Quan-You Lu
- College of Biotechnology, Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China; Key Laboratory of Genetic Improvement of Silkworm and Mulberry, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu 212100, China.
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Alazem M, Bwalya J, Pai H, Yu J, Cam HC, Burch-Smith T, Kim KH. Viral synergism suppresses R gene-mediated resistance by impairing downstream defense mechanisms in soybean. PLANT PHYSIOLOGY 2023:kiad255. [PMID: 37099452 PMCID: PMC10400036 DOI: 10.1093/plphys/kiad255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/24/2023] [Accepted: 04/24/2023] [Indexed: 06/19/2023]
Abstract
Viral synergism occurs when mixed infection of a susceptible plant by two or more viruses leads to increased susceptibility to at least one of the viruses. However, the ability of one virus to suppress R gene-controlled resistance against another virus has never been reported. In soybean (Glycine max) extreme resistance (ER) against soybean mosaic virus (SMV), governed by the Rsv3 R-protein, manifests a swift asymptomatic resistance against the avirulent strain SMV-G5H. Still, the mechanism by which Rsv3 confers ER is not fully understood. Here, we show that viral synergism broke this resistance by impairing downstream defense mechanisms triggered by Rsv3 activation. We found that activation of the antiviral RNA silencing pathway and the proimmune mitogen-activated protein kinase 3 (MAPK3), along with the suppression of the proviral MAPK6, are hallmarks of Rsv3-mediated ER against SMV-G5H. Surprisingly, infection with bean pod mottle virus (BPMV) disrupted this ER, allowing SMV-G5H to accumulate in Rsv3-containing plants. BPMV subverted downstream defenses by impairing the RNA silencing pathway and activating MAPK6. Further, BPMV reduced the accumulation of virus-related siRNAs and increased the virus-activated siRNA that targeted several defense-related nucleotide-binding leucine-rich-repeat receptors (NLRs) genes through the action of the suppression of RNA-silencing activities encoded in its large and small coat protein subunits. These results illustrate that viral synergism can result from abolishing highly specific R gene resistance by impairing active mechanisms downstream of the R gene.
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Affiliation(s)
- Mazen Alazem
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, Republic of Korea
- The Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
| | - John Bwalya
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hsuan Pai
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Jisuk Yu
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, Republic of Korea
| | - Huong Chu Cam
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | | | - Kook-Hyung Kim
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, Republic of Korea
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
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Qin Y, Zhao J, Wang J, Ye X, Zhou C, Zhou Y. Regulation of Nicotiana benthamiana cell death induced by citrus chlorotic dwarf-associated virus-RepA protein by WRKY 1. FRONTIERS IN PLANT SCIENCE 2023; 14:1164416. [PMID: 37180388 PMCID: PMC10167294 DOI: 10.3389/fpls.2023.1164416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 04/10/2023] [Indexed: 05/16/2023]
Abstract
Citrus chlorotic dwarf-associated virus (CCDaV) is a Citlodavirus species in the Geminiviridae family that causes tremendous economic loss to the citrus industry in China. Some proteins encoded by geminiviruses are crucial for the interaction between the virus and its host plant. However, the exact functions of CCDaV-encoded proteins such as CCDaV-RepA have not been investigated. This study presents evidence that CCDaV-RepA elicits a hypersensitive response (HR)-like cell death in Nicotiana benthamiana that was accompanied by the production of H2O2 and ion leakage, which suggested that CCDaV-RepA is a potential recognition target for inducing host defense responses. Furthermore, the rolling-circle replication motifs of CCDaV-RepA are associated with triggering HR-like cell death in N. benthamiana. Confocal microscopy and deletion mutagenesis assays showed that CCDaV-RepA was located in the nucleus, while the first eight amino acids (aa) at the N terminus and two regions located between aa residues 122-263 and 220-264 of RepA were not associated with nuclear localization. Tobacco rattle virus-induced gene silencing of the key signaling cascade components revealed that HR-like cell death induced by RepA was inhibited in WRKY1-silenced N. benthamiana. Moreover, WRKY1 expression was upregulated in RepA-GFP infiltrated Overall, the results suggest that NbWRKY1 positively regulated CCDaV-RepA -induced cell death in N. benthamiana. These findings provide novel information for further research on the interactions between CCDaV and the host plant.
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Affiliation(s)
| | | | | | | | | | - Yan Zhou
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing, China
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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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Orchid fleck dichorhavirus movement protein shows RNA silencing suppressor activity. J Gen Virol 2022; 103. [DOI: 10.1099/jgv.0.001805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
To counteract RNA interference-mediated antiviral defence, virus genomes evolved to express proteins that inhibit this plant defence mechanism. Using six independent biological approaches, we show that orchid fleck dichorhavirus citrus strain (OFV-citrus) movement protein (MP) may act as a viral suppressor of RNA silencing (VSR). By using the alfalfa mosaic virus (AMV) RNA 3 expression vector, it was observed that the MP triggered necrosis response in transgenic tobacco leaves and increased the viral RNA (vRNA) accumulation. The use of the potato virus X (PVX) expression system revealed that the cis expression of MP increased both the severity of the PVX infection and the accumulation of PVX RNAs, further supporting that MP could act as an RNA silencing suppressor (RSS). From the analysis of the RSS-defective turnip crinkle virus (TCV), we do not find local RSS activity for MP, suggesting a link between MP suppressor activity and the prevention of systemic silencing. In the analysis of local suppressive activity using the GFP-based agroinfiltration assay in Nicotiana benthamiana (16 c line), we do not identify local RSS activity for the five OFV RNA1-encoded proteins. However, when evaluating the small interfering RNA (siRNA) accumulation, we find that the expression of MP significantly reduces the accumulation of GFP-derived siRNA. Finally, we examine whether the MP can prevent systemic silencing in 16c plants. Our findings show that MP inhibits the long-distance spread of RNA silencing, but does not affect the short-distance spread. Together, our findings indicate that MP is part of OFV’s counter-defence mechanism, acting mainly in the prevention of systemic long-distance silencing. This work presents the first report of a VSR for a member of the genus Dichorhavirus.
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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: 0] [Impact Index Per Article: 0] [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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Chen C, Du M, Peng D, Li W, Xu J, Yang X, Zhou X. A Distinct Tobamovirus Associated With Trichosanthes kirilowii Mottle Mosaic Disease. Front Microbiol 2022; 13:927230. [PMID: 35801111 PMCID: PMC9253623 DOI: 10.3389/fmicb.2022.927230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 05/25/2022] [Indexed: 11/13/2022] Open
Abstract
Trichosanthes kirilowii is one of the most important perennial herbaceous vines that have been used in traditional Chinese medicine. In this study, a novel RNA virus was discovered in T. kirilowii plants showing leaf mottling and mosaic symptoms. The complete genome of this virus is 6,524 nucleotides long and encodes four open reading frames which are arranged in a manner typical of tobamoviruses. Phylogenetic analysis based on the complete genome sequence revealed that the virus was clustered into a branch with the tobamoviruses whose natural host are plants belonging to the family Cucurbitaceae. A full-length infectious cDNA clone was then constructed and demonstrated to establish a systemic infection with typical symptoms in Nicotiana benthamiana, T. kirilowii, and five other cucurbitaceous crops including Cucumis melo, C. lanatus, C. sativus, Luffa aegyptiaca, and Cucurbita pepo via agrobacterium-mediated infectivity assays. Further experiments provided evidence that the rod-shaped viral particles derived from the infectious clone could be mechanically transmitted and reproduce indistinguishable symptoms in the tested plants. Taken together, the mottle mosaic disease of T. kirilowii is caused by a distinct tobamovirus, for which the name Trichosanthes mottle mosaic virus (TrMMV) is proposed. As the infectious cDNA clone of TrMMV could also infect five other cucurbit crops, this distinct tobamovirus could be a potential threat to other cucurbitaceous crops.
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Affiliation(s)
- Cheng Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Institute of Plant Protection, Sichuan Academy of Agricultural Sciences, Key Laboratory of Integrated Pest Management on Crops in Southwest, Ministry of Agriculture, Chengdu, China
| | - Min Du
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Deliang Peng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wulun Li
- Service Center of Qianshan Plant-Products Industry, Qianshan, China
| | - Jingfeng Xu
- Service Center of Qianshan Plant-Products Industry, Qianshan, China
| | - Xiuling Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Xiuling Yang,
| | - Xueping Zhou
- State Key Laboratory for Biology of Plant Diseases 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
- Xueping Zhou,
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11
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Fan L, He C, Gao D, Xu T, Xing F, Yan J, Zhan B, Li S, Wang H. Identification of Silencing Suppressor Protein Encoded by Strawberry Mottle Virus. FRONTIERS IN PLANT SCIENCE 2022; 13:786489. [PMID: 35712581 PMCID: PMC9195133 DOI: 10.3389/fpls.2022.786489] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 04/29/2022] [Indexed: 06/15/2023]
Abstract
Strawberry mottle virus (SMoV) is associated with strawberry decline disease, causing losses to fruit yield and quality. In this study, using a screening system that enables detection of both local and systemic plant host (RNA silencing) defense responses, we found that Pro2Glu and P28, encoded by SMoV RNA2 genome, functioned to suppress local and systemic RNA silencing triggered by single- but not double-stranded GFP RNA. Subcellular localization assay revealed that both Pro2Glu and P28 were localized to nucleus and cytoplasm. The deletion of 11 amino acid residues at the C-terminus destabilized Pro2Glu protein, and the disruption of two conserved GW motifs deprived Pro2Glu of ability to suppress RNA silencing. Additionally, SMoV Pro2Glu and P28 enhanced the accumulation of potato virus X (PVX) in Nicotiana benthamiana 22 days post-infiltration, and P28 exacerbated significantly the symptoms of PVX. Collectively, these data indicate that the genome of SMoV RNA2 encodes two suppressors of RNA silencing. This is the first identification of a stramovirus suppressor of RNA silencing.
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Affiliation(s)
- Lingjiao Fan
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
| | - Chengyong He
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
| | - Dehang Gao
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
| | - Tengfei Xu
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
| | - Fei Xing
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiaqi Yan
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
| | - Binhui Zhan
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shifang Li
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hongqing Wang
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing, China
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12
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Du M, Wang Y, Chen C, Li X, Feng R, Zhou X, Yang X. Molecular Characterization and Pathogenicity of a Novel Soybean-Infecting Monopartite Geminivirus in China. Viruses 2022; 14:341. [PMID: 35215936 PMCID: PMC8877103 DOI: 10.3390/v14020341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 01/31/2022] [Accepted: 02/06/2022] [Indexed: 02/06/2023] Open
Abstract
Soybean is a major legume crop that plays an important role in food production, industrial production, and animal husbandry. Here, we characterize a novel soybean-infecting monopartite geminivirus identified in China. Analysis of the contigs de novo assembled from sequenced small interfering RNAs, followed by PCR, cloning, and sequencing, the complete viral genome was determined to be 2782 nucleotides. The genome contains the conserved nonanucleotide sequence, TAATATTAC and other sequence features typical of the family Geminiviridae, and encodes two and four open reading frames in the virion-sense and the complementary-sense strands, respectively. Genome-wide pairwise identity analysis revealed that the novel virus shares less than 65.6% identity with previously characterized geminiviruses. Phylogenetic and recombination analysis indicated that this virus was placed in a unique taxon within the family Geminiviridae and potentially arose from recombination. An infectious clone of this virus was further constructed and its infectivity was tested in different species of plants. Successful infection and characteristic symptoms were observed in Glycine max, Nicotiana benthamiana, N. tabacum, N. glutinosa, and N. tabacum cv. Samsun plants. Taken together, this virus represents a member of an unclassified genus of the family Geminiviridae, for which the name soybean yellow leaf curl virus is proposed.
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Affiliation(s)
- Min Du
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (M.D.); (Y.W.); (C.C.); (R.F.)
| | - Yongzhi Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (M.D.); (Y.W.); (C.C.); (R.F.)
- Key Laboratory of Integrated Pest Management on Crops in Northeast, Ministry of Agriculture, Jilin Academy of Agricultural Sciences, Changchun 130033, China;
| | - Cheng Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (M.D.); (Y.W.); (C.C.); (R.F.)
- Key Laboratory of Integrated Pest Management on Crops in Southwest, Institute of Plant Protection, Ministry of Agriculture, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China
| | - Xiaoyu Li
- Key Laboratory of Integrated Pest Management on Crops in Northeast, Ministry of Agriculture, Jilin Academy of Agricultural Sciences, Changchun 130033, China;
| | - Runzi Feng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (M.D.); (Y.W.); (C.C.); (R.F.)
| | - 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; (M.D.); (Y.W.); (C.C.); (R.F.)
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - 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; (M.D.); (Y.W.); (C.C.); (R.F.)
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13
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Sun S, Ren Y, Wang D, Farooq T, He Z, Zhang C, Li S, Yang X, Zhou X. A group I WRKY transcription factor regulates mulberry mosaic dwarf-associated virus-triggered cell death in Nicotiana benthamiana. MOLECULAR PLANT PATHOLOGY 2022; 23:237-253. [PMID: 34738705 PMCID: PMC8743015 DOI: 10.1111/mpp.13156] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 05/27/2023]
Abstract
Geminiviruses constitute the largest group of known plant viruses and cause devastating losses to a wide range of crops and woody plants globally. Mulberry mosaic dwarf-associated virus (MMDaV), identified from Chinese mulberry trees via small RNA-based deep sequencing, is a divergent monopartite geminivirus belonging to the genus Mulcrilevirus of the family Geminiviridae. Previous studies have shown that plants employ multiple layers of defence to protect themselves from geminivirus infection. The interplay between plant and MMDaV is nevertheless less studied. This study presents evidence that MMDaV triggers hypersensitive response (HR)-mediated antiviral defence in Nicotiana benthamiana plants. We show that the RepA protein of MMDaV is engaged in HR-type cell death induction. We find that the RepA mutants with compromised nuclear localization ability impair their capabilities of cell death induction. Virus-induced gene silencing of the key components of the R protein-mediated signalling pathway reveals that down-regulation of the nucleus-targeting NbWRKY1 alleviates the cell death induction activity of RepA. We further demonstrate that RepA up-regulates the transcript level of NbWRKY1. Furthermore, expression of RepA in N. benthamiana confers plant resistance against two begomoviruses. We propose that plant resistance against RepA can be potentially used to improve plant defence against geminiviruses in crops.
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Affiliation(s)
- Shaoshuang Sun
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Yanxiang Ren
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Dongxue Wang
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Tahir Farooq
- Plant Protection Research InstituteGuangdong Academy of Agricultural SciencesGuangzhouChina
| | - Zifu He
- Plant Protection Research InstituteGuangdong Academy of Agricultural SciencesGuangzhouChina
| | - Chao Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Shifang Li
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Xiuling Yang
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Xueping Zhou
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
- State Key Laboratory of Rice Biology, Institute of BiotechnologyZhejiang UniversityHangzhouChina
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14
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Zhai Y, Roy A, Peng H, Mullendore DL, Kaur G, Mandal B, Mukherjee SK, Pappu HR. Identification and Functional Analysis of Four RNA Silencing Suppressors in Begomovirus Croton Yellow Vein Mosaic Virus. FRONTIERS IN PLANT SCIENCE 2022; 12:768800. [PMID: 35069624 PMCID: PMC8777275 DOI: 10.3389/fpls.2021.768800] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/30/2021] [Indexed: 06/01/2023]
Abstract
Croton yellow vein mosaic virus (CYVMV), a species in the genus Begomovirus, is a prolific monopartite begomovirus in the Indian sub-continent. CYVMV infects multiple crop plants to cause leaf curl disease. Plants have developed host RNA silencing mechanisms to defend the threat of viruses, including CYVMV. We characterized four RNA silencing suppressors, namely, V2, C2, and C4 encoded by CYVMV and betasatellite-encoded C1 protein (βC1) encoded by the cognate betasatellite, croton yellow vein betasatellite (CroYVMB). Their silencing suppressor functions were verified by the ability of restoring the β-glucuronidase (GUS) activity suppressed by RNA silencing. We showed here for the first time that V2 was capable of self-interacting, as well as interacting with the V1 protein, and could be translocalized to the plasmodesmata in the presence of CYVMV. The knockout of either V2 or V1 impaired the intercellular mobility of CYVMV, indicating their novel coordinated roles in the cell-to-cell movement of the virus. As pathogenicity determinants, each of V2, C2, and C4 could induce typical leaf curl symptoms in Nicotiana benthamiana plants even under transient expression. Interestingly, the transcripts and proteins of all four suppressors could be detected in the systemically infected leaves with no correlation to symptom induction. Overall, our work identifies four silencing suppressors encoded by CYVMV and its cognate betasatellite and reveals their subcellular localizations, interaction behavior, and roles in symptom induction and intercellular virus movement.
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Affiliation(s)
- Ying Zhai
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
| | - Anirban Roy
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Hao Peng
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
| | - Daniel L. Mullendore
- Franceschi Microscopy and Imaging Center, Washington State University, Pullman, WA, United States
| | - Gurpreet Kaur
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Bikash Mandal
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Sunil Kumar Mukherjee
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Hanu R. Pappu
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
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15
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Decle-Carrasco S, Rodríguez-Zapata LC, Castano E. Plant viral proteins and fibrillarin: the link to complete the infective cycle. Mol Biol Rep 2021; 48:4677-4686. [PMID: 34036480 DOI: 10.1007/s11033-021-06401-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/08/2021] [Indexed: 10/21/2022]
Abstract
The interaction between viruses with the nucleolus is already a well-defined field of study in plant virology. This interaction is not restricted to those viruses that replicate in the nucleus, in fact, RNA viruses that replicate exclusively in the cytoplasm express proteins that localize in the nucleolus. Some positive single stranded RNA viruses from animals and plants have been reported to interact with the main nucleolar protein, Fibrillarin. Among nucleolar proteins, Fibrillarin is an essential protein that has been conserved in sequence and function throughout evolution. Fibrillarin is a methyltransferase protein with more than 100 methylation sites in the pre-ribosomal RNA, involved in multiple cellular processes, including initiation of transcription, oncogenesis, and apoptosis, among others. Recently, it was found that AtFib2 shows a ribonuclease activity. In plant viruses, Fibrillarin is involved in long-distance movement and cell-to-cell movement, being two highly different processes. The mechanism that Fibrillarin performs is still unknown. However, and despite belonging to very different viral families, the majority comply with the following. (1) They are positive single stranded RNA viruses; (2) encode different types of viral proteins that partially localize in the nucleolus; (3) interacts with Fibrillarin exporting it to the cytoplasm; (4) the viral protein-Fibrillarin interaction forms an RNP complex with the viral RNA and; (5) Fibrillarin depletion affects the infective cycle of the virus. Here we review the relationship of those plant viruses with Fibrillarin interaction, with special focus on the molecular processes of the virus to sequester Fibrillarin to complete its infective cycle.
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Affiliation(s)
- Stefano Decle-Carrasco
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Luis Carlos Rodríguez-Zapata
- Unidad de Biotecnología. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Enrique Castano
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México.
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16
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Decle-Carrasco S, Rodríguez-Zapata LC, Castano E. Plant viral proteins and fibrillarin: the link to complete the infective cycle. Mol Biol Rep 2021. [PMID: 34036480 DOI: 10.1007/s11033-021-06401-1/tables/1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
The interaction between viruses with the nucleolus is already a well-defined field of study in plant virology. This interaction is not restricted to those viruses that replicate in the nucleus, in fact, RNA viruses that replicate exclusively in the cytoplasm express proteins that localize in the nucleolus. Some positive single stranded RNA viruses from animals and plants have been reported to interact with the main nucleolar protein, Fibrillarin. Among nucleolar proteins, Fibrillarin is an essential protein that has been conserved in sequence and function throughout evolution. Fibrillarin is a methyltransferase protein with more than 100 methylation sites in the pre-ribosomal RNA, involved in multiple cellular processes, including initiation of transcription, oncogenesis, and apoptosis, among others. Recently, it was found that AtFib2 shows a ribonuclease activity. In plant viruses, Fibrillarin is involved in long-distance movement and cell-to-cell movement, being two highly different processes. The mechanism that Fibrillarin performs is still unknown. However, and despite belonging to very different viral families, the majority comply with the following. (1) They are positive single stranded RNA viruses; (2) encode different types of viral proteins that partially localize in the nucleolus; (3) interacts with Fibrillarin exporting it to the cytoplasm; (4) the viral protein-Fibrillarin interaction forms an RNP complex with the viral RNA and; (5) Fibrillarin depletion affects the infective cycle of the virus. Here we review the relationship of those plant viruses with Fibrillarin interaction, with special focus on the molecular processes of the virus to sequester Fibrillarin to complete its infective cycle.
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Affiliation(s)
- Stefano Decle-Carrasco
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Luis Carlos Rodríguez-Zapata
- Unidad de Biotecnología. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Enrique Castano
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México.
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17
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Qiu Y, Zhang S, Yu H, Xuan Z, Yang L, Zhan B, Murilo Zerbini F, Cao M. Identification and Characterization of Two Novel Geminiviruses Associated with Paper Mulberry ( Broussonetia papyrifera) Leaf Curl Disease. PLANT DISEASE 2020; 104:3010-3018. [PMID: 32881645 DOI: 10.1094/pdis-12-19-2597-re] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Paper mulberry (Broussonetia papyrifera) is a perennial woody plant used as source material for Cai Lun paper making, in traditional Chinese medicine, and as livestock feed. To identify the presence of viruses in paper mulberry plants affected by a disease with leaf curl symptoms, high-throughput sequencing of total RNA was performed. Analysis of transcriptome libraries allowed the reconstruction of two geminivirus-like genomes. Rolling-circle amplification and PCR with back-to-back primers confirmed the presence of two geminiviruses with monopartite genomes in these plants, with the names paper mulberry leaf curl virus 1 and 2 (PMLCV-1 and PMLCV-2) proposed. The genomes of PMLCV-1 (3,056 nt) and PMLCV-2 (3,757 to 3,763 nt) encode six proteins, with the V4 protein of PMLCV-1 and the V3 proteins of both viruses having low similarities to any known protein in databases. Alternative splicing of an intron, akin to that of mastre-, becurto-, capula-, and grabloviruses, was identified by small RNA (sRNA)-seq and RNA-seq reads mapping to PMLCV-1 and PMLCV-2 antisense transcripts. Phylogenetic analyses and pairwise comparisons showed that PMLCV-1 and PMLCV-2 are most closely related to, but distinct from, two unassigned geminiviruses, citrus chlorotic dwarf associated virus and mulberry mosaic dwarf associated virus, suggesting that they are two new members of the family Geminiviridae. Field investigation confirmed the close association of the two viruses with leaf curl symptoms in paper mulberry plants and that coinfection can aggravate the symptoms.
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Affiliation(s)
- Yuanjian Qiu
- National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China
- Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China
| | - Song Zhang
- National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China
- Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China
| | - Haodong Yu
- National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China
- Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China
| | - Zhiyou Xuan
- National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China
- Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China
| | - Liu Yang
- National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China
- Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China
| | - Binhui Zhan
- State Key Laboratory for Biology of Plant Disease and Insect Pest, Institute of Plant Protection, Academy of Agricultural Sciences, Beijing 100193, China
| | - F Murilo Zerbini
- Departamento de Fitopatologia/BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil
| | - Mengji Cao
- National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China
- Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China
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18
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Wang D, Sun S, Ren Y, Li S, Yang X, Zhou X. RepA Promotes the Nucleolar Exclusion of the V2 Protein of Mulberry Mosaic Dwarf-Associated Virus. Front Microbiol 2020; 11:1828. [PMID: 32903838 PMCID: PMC7438950 DOI: 10.3389/fmicb.2020.01828] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 07/13/2020] [Indexed: 01/23/2023] Open
Abstract
Plant viruses have limited coding capacities so that they rely heavily on the expression of multifunctional viral proteins to achieve a successful infection. The functional specification of viral proteins is often related to their differential interaction with plant and viral components and somewhat depends on their localization to various subcellular compartments. In this study, we analyzed the intracellular localization of the V2 protein of Mulberry mosaic dwarf-associated virus (MMDaV), an unsigned species of the family Geminiviridae. We show that the V2 protein colocalizes with the nucleolar protein fibrillarin (NbFib2) in the nucleolus upon transient expression in the epidermal cells of Nicotiana benthamiana. A yeast-two hybrid assay, followed by bimolecular fluorescence complementation assays, demonstrated the specific interaction between V2 and NbFib2. Intriguingly, we find that the presence of MMDaV excludes the V2 protein from the nucleolus to nucleoplasm. We present evidence that the replication-associated protein A (RepA) protein of MMDaV interacts with V2 and enables the nucleolar exclusion of V2. We also show that, while V2 interacts with itself primarily in the nucleolus, the presence of RepA redirects the site of V2-V2 interaction from the nucleolus to the nucleoplasm. We further reveal that RepA promotes V2 out of the nucleolus presumably by directing the NbFib2-V2 complex from the nucleolus to the nucleoplasm. Considering the critical role of the nucleolus in plant virus infection, this RepA-dependent modulation of V2 nucleolar localization would be crucial for understanding the involvement of this subcellular compartment in plant-virus interactions.
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Affiliation(s)
- Dongxue Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shaoshuang Sun
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yanxiang Ren
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Shifang Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiuling Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xueping Zhou
- State Key Laboratory for Biology of Plant Diseases 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
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19
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Leastro MO, Castro DYO, Freitas-Astúa J, Kitajima EW, Pallás V, Sánchez-Navarro JÁ. Citrus Leprosis Virus C Encodes Three Proteins With Gene Silencing Suppression Activity. Front Microbiol 2020; 11:1231. [PMID: 32655520 PMCID: PMC7325951 DOI: 10.3389/fmicb.2020.01231] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 05/14/2020] [Indexed: 01/12/2023] Open
Abstract
Citrus leprosis virus C (CiLV-C) belongs to the genus Cilevirus, family Kitaviridae, and is considered the most devastating virus infecting citrus in Brazil, being the main viral pathogen responsible for citrus leprosis (CL), a severe disease that affects citrus orchards in Latin America. Here, proteins encoded by CiLV-C genomic RNA 1 and 2 were screened for potential RNA silencing suppressor (RSS) activity by five methods. Using the GFP-based reporter agroinfiltration assay, we have not found potential local suppressor activity for the five CiLV-C encoded proteins. However, when RSS activity was evaluated using the alfalfa mosaic virus (AMV) system, we found that the p29, p15, and p61 CiLV-C proteins triggered necrosis response and increased the AMV RNA 3 accumulation, suggesting a suppressive functionality. From the analysis of small interfering RNAs (siRNAs) accumulation, we observed that the ectopic expression of the p29, p15, and p61 reduced significantly the accumulation of GFP derived siRNAs. The use of the RSS defective turnip crinkle virus (TCV) system revealed that only the trans-expression of the p15 protein restored the cell-to-cell viral movement. Finally, the potato virus X (PVX) system revealed that the expression of p29, p15, and p61 increased the PVX RNA accumulation; in addition, the p29 and p15 enhanced the pathogenicity of PVX resulting in the death of tobacco plants. Furthermore, PVX-p61 infection resulted in a hypersensitive response (HR), suggesting that p61 could also activate a plant defense response mechanism. This is the first report describing the RSS activity for CiLV-C proteins and, moreover, for a member of the family Kitaviridae.
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Affiliation(s)
- Mikhail Oliveira Leastro
- Unidade Laboratorial de Referência em Biologia Molecular Aplicada, Instituto Biológico, São Paulo, Brazil.,Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científcas (CSIC), Valencia, Spain
| | - Deibis Yorlenis Ortega Castro
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científcas (CSIC), Valencia, Spain
| | - Juliana Freitas-Astúa
- Unidade Laboratorial de Referência em Biologia Molecular Aplicada, Instituto Biológico, São Paulo, Brazil.,Embrapa Mandioca e Fruticultura, Cruz das Almas, Brazil
| | - Elliot Watanabe Kitajima
- Departamento de Fitopatologia e Nematologia, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, Brazil
| | - Vicente Pallás
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científcas (CSIC), Valencia, Spain
| | - Jesús Ángel Sánchez-Navarro
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científcas (CSIC), Valencia, Spain
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20
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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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21
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Superinfection by PHYVV Alters the Recovery Process in PepGMV-Infected Pepper Plants. Viruses 2020; 12:v12030286. [PMID: 32151060 PMCID: PMC7150747 DOI: 10.3390/v12030286] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/20/2020] [Accepted: 02/25/2020] [Indexed: 01/02/2023] Open
Abstract
Geminiviruses are important plant pathogens that affect crops around the world. In some geminivirus-host interactions, infected plants show recovery, a phenomenon characterized by symptom disappearance in newly emerging leaves. In pepper-Pepper golden mosaic virus (PepGMV) interaction, the host recovery process involves a silencing mechanism that includes both post-transcriptional (PTGS) and transcriptional (TGS) gene silencing pathways. Under field conditions, PepGMV is frequently found in mixed infections with Pepper huasteco yellow vein virus (PHYVV), another bipartite begomovirus. Mixed infected plants generally show a synergetic phenomenon and do not present recovery. Little is known about the molecular mechanism of this interaction. In the present study, we explored the effect of superinfection by PHYVV on a PepGMV-infected pepper plant showing recovery. Superinfection with PHYVV led to (a) the appearance of severe symptoms, (b) an increase of the levels of PepGMV DNA accumulation, (c) a decrease of the relative methylation levels of PepGMV DNA, and (d) an increase of chromatin activation marks present in viral minichromosomes. Finally, using heterologous expression and silencing suppression reporter systems, we found that PHYVV REn presents TGS silencing suppressor activity, whereas similar experiments suggest that Rep might be involved in suppressing PTGS.
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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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Structure and Activity of a Cytosolic Ribosome-Inactivating Protein from Rice. Toxins (Basel) 2019; 11:toxins11060325. [PMID: 31174339 PMCID: PMC6628440 DOI: 10.3390/toxins11060325] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 05/30/2019] [Accepted: 06/04/2019] [Indexed: 02/07/2023] Open
Abstract
Ribosome-inactivating proteins (RIPs) are cytotoxic enzymes that inhibit protein translation by depurinating ribosomal RNA. Although most plant RIPs are synthesized with leader sequences that sequester them away from the host ribosomes, several RIPs from cereals lack these signal peptides and therefore probably reside in the cytosol near the plant ribosomes. More than 30 RIP genes have been identified in the rice (Oryza sativa spp. japonica) genome, many of them lacking a signal peptide. This paper focuses on a presumed cytosolic type-1 RIP from rice, referred to as OsRIP1. Using 3D modeling it is shown that OsRIP1 structurally resembles other cereal RIPs and has an active site that meets the requirements for activity. Furthermore, localization studies indicate that OsRIP1-eGFP fusion proteins reside in the nucleocytoplasmic space when expressed in epidermal cells of Nicotiana benthamiana or Arabidopsis thaliana suspension cells. Finally, OsRIP1 was recombinantly produced in Escherichia coli and was demonstrated to possess catalytic activity. Interestingly, this recombinant RIP inactivates wheat ribosomes far less efficiently than rabbit ribosomes in an in vitro system. These findings raise some interesting questions concerning the mode of action and physiological role of OsRIP1. This is the first time a RIP from rice is investigated at protein level and is shown to possess biological activity.
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