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Yue N, Jiang Z, Pi Q, Yang M, Gao Z, Wang X, Zhang H, Wu F, Jin X, Li M, Wang Y, Zhang Y, Li D. Zn2+-dependent association of cysteine-rich protein with virion orchestrates morphogenesis of rod-shaped viruses. PLoS Pathog 2024; 20:e1012311. [PMID: 38885273 DOI: 10.1371/journal.ppat.1012311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 05/31/2024] [Indexed: 06/20/2024] Open
Abstract
The majority of rod-shaped and some filamentous plant viruses encode a cysteine-rich protein (CRP) that functions in viral virulence; however, the roles of these CRPs in viral infection remain largely unknown. Here, we used barley stripe mosaic virus (BSMV) as a model to investigate the essential role of its CRP in virus morphogenesis. The CRP protein γb directly interacts with BSMV coat protein (CP), the mutations either on the His-85 site in γb predicted to generate a potential CCCH motif or on the His-13 site in CP exposed to the surface of the virions abolish the zinc-binding activity and their interaction. Immunogold-labeling assays show that γb binds to the surface of rod-shaped BSMV virions in a Zn2+-dependent manner, which enhances the RNA binding activity of CP and facilitates virion assembly and stability, suggesting that the Zn2+-dependent physical association of γb with the virion is crucial for BSMV morphogenesis. Intriguingly, the tightly binding of diverse CRPs to their rod-shaped virions is a general feature employed by the members in the families Virgaviridae (excluding the genus Tobamovirus) and Benyviridae. Together, these results reveal a hitherto unknown role of CRPs in the assembly and stability of virus particles, and expand our understanding of the molecular mechanism underlying virus morphogenesis.
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Affiliation(s)
- Ning Yue
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Zhihao Jiang
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Qinglin Pi
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Meng Yang
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Zongyu Gao
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xueting Wang
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
| | - He Zhang
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Fengtong Wu
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xuejiao Jin
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Menglin Li
- College of Plant Protection, China Agricultural University, Beijing, China
| | - Ying Wang
- College of Plant Protection, China Agricultural University, Beijing, China
| | - Yongliang Zhang
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Dawei Li
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China
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Zhuang X, Guo X, Gu T, Xu X, Qin L, Xu K, He Z, Zhang K. Phosphorylation of plant virus proteins: Analysis methods and biological functions. Front Microbiol 2022; 13:935735. [PMID: 35958157 PMCID: PMC9360750 DOI: 10.3389/fmicb.2022.935735] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
Phosphorylation is one of the most extensively investigated post-translational modifications that orchestrate a variety of cellular signal transduction processes. The phosphorylation of virus-encoded proteins plays an important regulatory role in the infection cycle of such viruses in plants. In recent years, molecular mechanisms underlying the phosphorylation of plant viral proteins have been widely studied. Based on recent publications, our study summarizes the phosphorylation analyses of plant viral proteins and categorizes their effects on biological functions according to the viral life cycle. This review provides a theoretical basis for elucidating the molecular mechanisms of viral infection. Furthermore, it deepens our understanding of the biological functions of phosphorylation in the interactions between plants and viruses.
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Affiliation(s)
- Xinjian Zhuang
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Xiao Guo
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Tianxiao Gu
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Xiaowei Xu
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Lang Qin
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Kai Xu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Zhen He
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Kun Zhang
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China,Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China,*Correspondence: Kun Zhang, ;
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3
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Yue N, Jiang Z, Zhang X, Li Z, Wang X, Wen Z, Gao Z, Pi Q, Zhang Y, Wang X, Han C, Yu J, Li D. Palmitoylation of γb protein directs a dynamic switch between Barley stripe mosaic virus replication and movement. EMBO J 2022; 41:e110060. [PMID: 35642376 PMCID: PMC9251889 DOI: 10.15252/embj.2021110060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 04/28/2022] [Accepted: 05/05/2022] [Indexed: 11/09/2022] Open
Abstract
Viral replication and movement are intimately linked; however, the molecular mechanisms regulating the transition between replication and subsequent movement remain largely unknown. We previously demonstrated that the Barley stripe mosaic virus (BSMV) γb protein promotes viral replication and movement by interacting with the αa replicase and TGB1 movement proteins. Here, we found that γb is palmitoylated at Cys-10, Cys-19, and Cys-60 in Nicotiana benthamiana, which supports BSMV infection. Intriguingly, non-palmitoylated γb is anchored to chloroplast replication sites and enhances BSMV replication, whereas palmitoylated γb protein recruits TGB1 to the chloroplasts and forms viral replication-movement intermediate complexes. At the late stages of replication, γb interacts with NbPAT15 and NbPAT21 and is palmitoylated at the chloroplast periphery, thereby shifting viral replication to intracellular and intercellular movement. We also show that palmitoylated γb promotes virus cell-to-cell movement by interacting with NbREM1 to inhibit callose deposition at the plasmodesmata. Altogether, our experiments reveal a model whereby palmitoylation of γb directs a dynamic switch between BSMV replication and movement events during infection.
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Affiliation(s)
- Ning Yue
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Zhihao Jiang
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Xuan Zhang
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Zhenggang Li
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Xueting Wang
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Zhiyan Wen
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Zongyu Gao
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Qinglin Pi
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Yongliang Zhang
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Xian‐Bing Wang
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Chenggui Han
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Jialin Yu
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Dawei Li
- State Key Laboratory of Agro‐Biotechnology, College of Biological SciencesChina Agricultural UniversityBeijingChina
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4
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Jiang Z, Jin X, Yang M, Pi Q, Cao Q, Li Z, Zhang Y, Wang XB, Han C, Yu J, Li D. Barley stripe mosaic virus γb protein targets thioredoxin h-type 1 to dampen salicylic acid-mediated defenses. PLANT PHYSIOLOGY 2022; 189:1715-1727. [PMID: 35325212 PMCID: PMC9237698 DOI: 10.1093/plphys/kiac137] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/27/2022] [Indexed: 05/14/2023]
Abstract
Salicylic acid (SA) acts as a signaling molecule to perceive and defend against pathogen infections. Accordingly, pathogens evolve versatile strategies to disrupt the SA-mediated signal transduction, and how plant viruses manipulate the SA-dependent defense responses requires further characterization. Here, we show that barley stripe mosaic virus (BSMV) infection activates the SA-mediated defense signaling pathway and upregulates the expression of Nicotiana benthamiana thioredoxin h-type 1 (NbTRXh1). The γb protein interacts directly with NbTRXh1 in vivo and in vitro. The overexpression of NbTRXh1, but not a reductase-defective mutant, impedes BSMV infection, whereas low NbTRXh1 expression level results in increased viral accumulation. Similar with its orthologs in Arabidopsis (Arabidopsis thaliana), NbTRXh1 also plays an essential role in SA signaling transduction in N. benthamiana. To counteract NbTRXh1-mediated defenses, the BSMV γb protein targets NbTRXh1 to dampen its reductase activity, thereby impairing downstream SA defense gene expression to optimize viral cell-to-cell movement. We also found that NbTRXh1-mediated resistance defends against lychnis ringspot virus, beet black scorch virus, and beet necrotic yellow vein virus. Taken together, our results reveal a role for the multifunctional γb protein in counteracting plant defense responses and an expanded broad-spectrum antibiotic role of the SA signaling pathway.
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Affiliation(s)
- Zhihao Jiang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Xuejiao Jin
- State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, PR China
| | - Meng Yang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Qinglin Pi
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Qing Cao
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Zhenggang Li
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Yongliang Zhang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Xian-Bing Wang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Chenggui Han
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Jialin Yu
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Dawei Li
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
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5
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Li Z, Yang X, Li W, Wen Z, Duan J, Jiang Z, Zhang D, Xie X, Wang X, Li F, Li D, Zhang Y. SAMDC3 enhances resistance to Barley stripe mosaic virus by promoting the ubiquitination and proteasomal degradation of viral γb protein. THE NEW PHYTOLOGIST 2022; 234:618-633. [PMID: 35075654 DOI: 10.1111/nph.17993] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Posttranslational modifications (PTMs) play important roles in virus-host interplay. We previously demonstrated that Barley stripe mosaic virus (BSMV) γb protein is phosphorylated by different host kinases to support or impede viral infection. However, whether and how other types of PTMs participate in BSMV infection remains to be explored. Here, we report that S-adenosylmethionine decarboxylase 3 (SAMDC3) from Nicotiana benthamiana or wheat (Triticum aestivum) interacts with γb. BSMV infection induced SAMDC3 expression. Overexpression of SAMDC3 led to the destabilization of γb and reduction in viral infectivity, whereas knocking out NbSAMDC3 increased susceptibility to BSMV. NbSAMDC3 positively regulated the 26S proteasome-mediated degradation of γb via its PEST domain. Further mechanistic studies revealed that γb can be ubiquitinated in planta and that NbSAMDC3 promotes the proteasomal degradation of γb by increasing γb ubiquitination. We also found evidence that ubiquitination occurs at nonlysine residues (Ser-133 and Cys-144) within γb. Together, our results provide a function for SAMDC3 in defence against BSMV infection through targeting of γb abundance, which contributes to our understanding of how a plant host deploys the ubiquitin-proteasome system to mount defences against viral infections.
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Affiliation(s)
- Zhaolei 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
| | - Xinxin Yang
- 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
| | - Wenli 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
| | - Zhiyan Wen
- 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
| | - Jiangning Duan
- 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
| | - Zhihao Jiang
- 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
| | - Dingliang Zhang
- 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
| | - Xialin Xie
- 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
| | - Xueting Wang
- 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
| | - 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
| | - 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
| | - Yongliang Zhang
- 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
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6
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Wang X, Jiang Z, Yue N, Jin X, Zhang X, Li Z, Zhang Y, Wang X, Han C, Yu J, Li D. Barley stripe mosaic virus γb protein disrupts chloroplast antioxidant defenses to optimize viral replication. EMBO J 2021; 40:e107660. [PMID: 34254679 PMCID: PMC8365260 DOI: 10.15252/embj.2021107660] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 06/10/2021] [Accepted: 06/17/2021] [Indexed: 01/21/2023] Open
Abstract
The plant antioxidant system plays important roles in response to diverse abiotic and biotic stresses. However, the effects of virus infection on host redox homeostasis and how antioxidant defense pathway is manipulated by viruses remain poorly understood. We previously demonstrated that the Barley stripe mosaic virus (BSMV) γb protein is recruited to the chloroplast by the viral αa replicase to enhance viral replication. Here, we show that BSMV infection induces chloroplast oxidative stress. The versatile γb protein interacts directly with NADPH-dependent thioredoxin reductase C (NTRC), a core component of chloroplast antioxidant systems. Overexpression of NbNTRC significantly impairs BSMV replication in Nicotiana benthamiana plants, whereas disruption of NbNTRC expression leads to increased viral accumulation and infection severity. To counter NTRC-mediated defenses, BSMV employs the γb protein to competitively interfere with NbNTRC binding to 2-Cys Prx. Altogether, this study indicates that beyond acting as a helicase enhancer, γb also subverts NTRC-mediated chloroplast antioxidant defenses to create an oxidative microenvironment conducive to viral replication.
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Affiliation(s)
- Xueting Wang
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Zhihao Jiang
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Ning Yue
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Xuejiao Jin
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Xuan Zhang
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Zhaolei Li
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Yongliang Zhang
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Xian‐Bing Wang
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Chenggui Han
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Jialin Yu
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Dawei Li
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil MicrobiologyCollege of Biological SciencesChina Agricultural UniversityBeijingChina
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7
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Jiang Z, Zhang K, Li Z, Li Z, Yang M, Jin X, Cao Q, Wang X, Yue N, Li D, Zhang Y. The Barley stripe mosaic virus γb protein promotes viral cell-to-cell movement by enhancing ATPase-mediated assembly of ribonucleoprotein movement complexes. PLoS Pathog 2020; 16:e1008709. [PMID: 32730331 PMCID: PMC7419011 DOI: 10.1371/journal.ppat.1008709] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 08/11/2020] [Accepted: 06/17/2020] [Indexed: 02/07/2023] Open
Abstract
Nine genera of viruses in five different families use triple gene block (TGB) proteins for virus movement. The TGB modules fall into two classes: hordei-like and potex-like. Although TGB-mediated viral movement has been extensively studied, determination of the constituents of the viral ribonucleoprotein (vRNP) movement complexes and the mechanisms underlying their involvement in vRNP-mediated movement are far from complete. In the current study, immunoprecipitation of TGB1 protein complexes formed during Barley stripe mosaic virus (BSMV) infection revealed the presence of the γb protein in the products. Further experiments demonstrated that TGB1 interacts with γb in vitro and in vivo, and that γb-TGB1 localizes at the periphery of chloroplasts and plasmodesmata (PD). Subcellular localization analyses of the γb protein in Nicotiana benthamiana epidermal cells indicated that in addition to chloroplast localization, γb also targets the ER, actin filaments and PD at different stages of viral infection. By tracking γb localization during BSMV infection, we demonstrated that γb is required for efficient cell-to-cell movement. The N-terminus of γb interacts with the TGB1 ATPase/helicase domain and enhances ATPase activity of the domain. Inactivation of the TGB1 ATPase activity also significantly impaired PD targeting. In vitro translation together with co-immunoprecipitation (co-IP) analyses revealed that TGB1-TGB3-TGB2 complex formation is enhanced by ATP hydrolysis. The γb protein positively regulates complex formation in the presence of ATP, suggesting that γb has a novel role in BSMV cell-to-cell movement by directly promoting TGB1 ATPase-mediated vRNP movement complex assembly. We further demonstrated that elimination of ATPase activity abrogates PD and actin targeting of Potato virus X (PVX) and Beet necrotic yellow vein virus (BNYVV) TGB1 proteins. These results expand our understanding of the multifunctional roles of γb and provide new insight into the functions of TGB1 ATPase domains in the movement of TGB-encoding viruses.
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Affiliation(s)
- Zhihao Jiang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Kun Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Zhaolei Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Zhenggang Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Meng Yang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Xuejiao Jin
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Qing Cao
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Xueting Wang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Ning Yue
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. 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, P. R. China
| | - Yongliang Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
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Li Z, Jiang Z, Yang X, Yue N, Wang X, Zhang K, Jackson AO, Li D, Zhang Y. Construction of an Infectious Poa semilatent virus cDNA Clone and Comparisons of Hordeivirus Cytopathology and Pathogenicity. PHYTOPATHOLOGY 2020; 110:215-227. [PMID: 31483225 DOI: 10.1094/phyto-06-19-0221-fi] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Poa semilatent virus (PSLV), Lychnis ringspot virus (LRSV), and Barley stripe mosaic virus (BSMV) are members of the genus Hordeivirus in the family Virgaviridae. However, the biological properties and molecular genetics of PSLV have not been compared with other hordeiviruses. Here, we have constructed an infectious cDNA clone of the PSLV Canadian strain and provided evidence that PSLV differs from BSMV and LRSV. First, unlike the other two hordeiviruses that replicate in chloroplasts, PSLV induces dramatic structural changes in peroxisome during its infection in barley. The αa replication protein also localizes to peroxisomes, suggesting that PSLV replication occurs in peroxisomes. Second, PSLV encodes a γb protein that shares 19 to 23% identity with those of other hordeiviruses, and its activity as a viral suppressor of RNA (VSR) silencing is distinct from those of BSMV and LRSV. Substitution of the BSMV γb protein with that of PSLV or LRSV revealed a negative correlation between VSR activity and symptom severity of the recombinant BSMV derivatives. Intriguingly, the Ser-Lys-Leu (SKL) peroxisome-targeting signals differ among γb proteins of various hordeiviruses, including some BSMV strains. The presence of the C-terminal SKL motif in the γb protein impairs its silencing suppressor activity and influences symptoms. Finally, we developed a PSLV-based virus-induced gene silencing vector that induced strong and effective silencing phenotypes of endogenous genes in barley, wheat, and millet. Our results shed new light on hordeivirus pathogenesis and evolution, and provide an alternative tool for genomics studies of model hosts and economically important monocots.
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Affiliation(s)
- Zhaolei 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
| | - Zhihao Jiang
- 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
| | - Xinxin Yang
- 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
| | - Ning Yue
- 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
| | - Xueting Wang
- 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
| | - Kun Zhang
- 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
| | - Andrew O Jackson
- Department of Plant and Microbial Biology, University of California-Berkeley, Berkeley, CA 94720, U.S.A
| | - 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
| | - Yongliang Zhang
- 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
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9
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Hu J, Li S, Li Z, Li H, Song W, Zhao H, Lai J, Xia L, Li D, Zhang Y. A barley stripe mosaic virus-based guide RNA delivery system for targeted mutagenesis in wheat and maize. MOLECULAR PLANT PATHOLOGY 2019; 20:1463-1474. [PMID: 31273916 PMCID: PMC6792137 DOI: 10.1111/mpp.12849] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plant RNA virus-based guide RNA (gRNA) delivery has substantial advantages compared to that of the conventional constitutive promoter-driven expression due to the rapid and robust amplification of gRNAs during virus replication and movement. To date, virus-induced genome editing tools have not been developed for wheat and maize. In this study, we engineered a barley stripe mosaic virus (BSMV)-based gRNA delivery system for clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9-mediated targeted mutagenesis in wheat and maize. BSMV-based delivery of single gRNAs for targeted mutagenesis was first validated in Nicotiana benthamiana. To extend this work, we transformed wheat and maize with the Cas9 nuclease gene and selected the wheat TaGASR7 and maize ZmTMS5 genes as targets to assess the feasibility and efficiency of BSMV-mediated mutagenesis. Positive targeted mutagenesis of the TaGASR7 and ZmTMS5 genes was achieved for wheat and maize with efficiencies of up to 78% and 48%. Our results provide a useful tool for fast and efficient delivery of gRNAs into economically important crops.
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Affiliation(s)
- Jiacheng Hu
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological SciencesChina Agricultural UniversityBeijing100193China
| | - Shaoya Li
- Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing100081China
| | - Zhaolei Li
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological SciencesChina Agricultural UniversityBeijing100193China
| | - Huiyuan Li
- Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing100081China
| | - Weibin Song
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and BreedingChina Agricultural UniversityBeijing100193China
| | - Haiming Zhao
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and BreedingChina Agricultural UniversityBeijing100193China
| | - Jinsheng Lai
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and BreedingChina Agricultural UniversityBeijing100193China
| | - Lanqin Xia
- Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing100081China
| | - Dawei Li
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological SciencesChina Agricultural UniversityBeijing100193China
| | - Yongliang Zhang
- State Key Laboratory of Agro‐Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological SciencesChina Agricultural UniversityBeijing100193China
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10
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Zhang X, Dong K, Xu K, Zhang K, Jin X, Yang M, Zhang Y, Wang X, Han C, Yu J, Li D. Barley stripe mosaic virus infection requires PKA-mediated phosphorylation of γb for suppression of both RNA silencing and the host cell death response. THE NEW PHYTOLOGIST 2018; 218:1570-1585. [PMID: 29453938 DOI: 10.1111/nph.15065] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/22/2018] [Indexed: 06/08/2023]
Abstract
The Barley stripe mosaic virus (BSMV) γb protein is a viral suppressor of RNA silencing (VSR) and symptom determinant. However, it is unclear how post-translational modification affects the different functions of γb. Here, we demonstrate that γb is phosphorylated at Ser-96 by a PKA-like kinase in vivo and in vitro. Mutant viruses containing a nonphosphorylatable substitution (BSMVS96A or BSMVS96R ) exhibited reduced viral accumulation in Nicotiana benthamiana due to transient induction of the cell death response that constrained the virus to necrotic areas. By contrast, a BSMVS96D mutant virus that mimics γb phosphorylation spread similarly to the wild-type virus. Furthermore, the S96A mutant had reduced local and systemic γb VSR activity due to having compromised its binding activity to 21-bp dsRNA. However, overexpression of other VSRs in trans or in cis failed to rescue the necrosis induced by BSMVS96A , demonstrating that suppression of cell death by γb phosphorylation is functionally distinct from its RNA silencing suppressor activities. These results provide new insights into the function of γb phosphorylation in regulating RNA silencing and the BSMV-induced host cell death response, and contribute to our understanding of how the virus optimizes the balance between viral replication and virus survival in the host plants during virus infection.
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Affiliation(s)
- Xuan Zhang
- 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
| | - Kai Dong
- 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
| | - Kai Xu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210046, China
| | - Kun Zhang
- 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
| | - Xuejiao Jin
- 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
| | - Meng Yang
- 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
| | - Yongliang Zhang
- 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
| | - Xianbing Wang
- 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
| | - Chenggui Han
- 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
| | - Jialin Yu
- 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
| | - 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
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11
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Zhang K, Zhang Y, Yang M, Liu S, Li Z, Wang X, Han C, Yu J, Li D. The Barley stripe mosaic virus γb protein promotes chloroplast-targeted replication by enhancing unwinding of RNA duplexes. PLoS Pathog 2017; 13:e1006319. [PMID: 28388677 PMCID: PMC5397070 DOI: 10.1371/journal.ppat.1006319] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/19/2017] [Accepted: 03/27/2017] [Indexed: 11/19/2022] Open
Abstract
RNA viruses encode various RNA binding proteins that function in many steps of viral infection cycles. These proteins function as RNA helicases, methyltransferases, RNA-dependent RNA polymerases, RNA silencing suppressors, RNA chaperones, movement proteins, and so on. Although many of the proteins bind the viral RNA genome during different stages of infection, our knowledge about the coordination of their functions is limited. In this study, we describe a novel role for the Barley stripe mosaic virus (BSMV) γb as an enhancer of αa RNA helicase activity, and we show that the γb protein is recruited by the αa viral replication protein to chloroplast membrane sites of BSMV replication. Mutagenesis or deletion of γb from BSMV resulted in reduced positive strand (+) RNAα accumulation, but γb mutations abolishing viral suppressor of RNA silencing (VSR) activity did not completely eliminate genomic RNA replication. In addition, cis- or trans-expression of the Tomato bushy stunt virus p19 VSR protein failed to complement the γb replication functions, indicating that the direct involvement of γb in BSMV RNA replication is independent of VSR functions. These data support a model whereby two BSMV-encoded RNA-binding proteins act coordinately to regulate viral genome replication and provide new insights into strategies whereby double-stranded viral RNA unwinding is regulated, as well as formation of viral replication complexes.
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Affiliation(s)
- Kun Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Yongliang Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Meng Yang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Songyu Liu
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Zhenggang Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Xianbing Wang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Chenggui Han
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Jialin Yu
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. 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, P. R. China
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12
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Janssens V, Zwaenepoel K, Rossé C, Petit MMR, Goris J, Parker PJ. PP2A binds to the LIM domains of lipoma-preferred partner through its PR130/B″ subunit to regulate cell adhesion and migration. J Cell Sci 2016; 129:1605-18. [PMID: 26945059 PMCID: PMC5333791 DOI: 10.1242/jcs.175778] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 02/18/2016] [Indexed: 01/23/2023] Open
Abstract
Here, we identify the LIM protein lipoma-preferred partner (LPP) as a binding partner of a specific protein phosphatase 2A (PP2A) heterotrimer that is characterised by the regulatory PR130/B″α1 subunit (encoded by PPP2R3A). The PR130 subunit interacts with the LIM domains of LPP through a conserved Zn²⁺-finger-like motif in the differentially spliced N-terminus of PR130. Isolated LPP-associated PP2A complexes are catalytically active. PR130 colocalises with LPP at multiple locations within cells, including focal contacts, but is specifically excluded from mature focal adhesions, where LPP is still present. An LPP-PR130 fusion protein only localises to focal adhesions upon deletion of the domain of PR130 that binds to the PP2A catalytic subunit (PP2A/C), suggesting that PR130-LPP complex formation is dynamic and that permanent recruitment of PP2A activity might be unfavourable for focal adhesion maturation. Accordingly, siRNA-mediated knockdown of PR130 increases adhesion of HT1080 fibrosarcoma cells onto collagen I and decreases their migration in scratch wound and Transwell assays. Complex formation with LPP is mandatory for these PR130-PP2A functions, as neither phenotype can be rescued by re-expression of a PR130 mutant that no longer binds to LPP. Our data highlight the importance of specific, locally recruited PP2A complexes in cell adhesion and migration dynamics.
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Affiliation(s)
- Veerle Janssens
- Francis Crick Institute, Protein Phosphorylation Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK Laboratory of Protein Phosphorylation and Proteomics, Dept. of Cellular and Molecular Medicine, KU Leuven, Herestraat 49 PO-box 901, Leuven B-3000, Belgium
| | - Karen Zwaenepoel
- Laboratory of Protein Phosphorylation and Proteomics, Dept. of Cellular and Molecular Medicine, KU Leuven, Herestraat 49 PO-box 901, Leuven B-3000, Belgium
| | - Carine Rossé
- Francis Crick Institute, Protein Phosphorylation Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK Research Centre, Institut Curie, Paris 75005, France
| | - Marleen M R Petit
- Molecular Oncology Laboratory, Dept. of Human Genetics, KU Leuven, Herestraat 49 PO-box 602, Leuven B-3000, Belgium
| | - Jozef Goris
- Laboratory of Protein Phosphorylation and Proteomics, Dept. of Cellular and Molecular Medicine, KU Leuven, Herestraat 49 PO-box 901, Leuven B-3000, Belgium
| | - Peter J Parker
- Francis Crick Institute, Protein Phosphorylation Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK Division of Cancer Studies King's College London, Guy's Hospital Campus, Thomas Street, London SE1 9RT, UK
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13
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Buhrow LM, Clark SM, Loewen MC. Identification of an attenuated barley stripe mosaic virus for the virus-induced gene silencing of pathogenesis-related wheat genes. PLANT METHODS 2016; 12:12. [PMID: 26839581 PMCID: PMC4736275 DOI: 10.1186/s13007-016-0112-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/19/2016] [Indexed: 05/21/2023]
Abstract
BACKGROUND Virus-induced gene silencing (VIGS) has become an emerging technology for the rapid, efficient functional genomic screening of monocot and dicot species. The barley stripe mosaic virus (BSMV) has been described as an effective VIGS vehicle for the evaluation of genes involved in wheat and barley phytopathogenesis; however, these studies have been obscured by BSMV-induced phenotypes and defense responses. The utility of BSMV VIGS may be improved using a BSMV genetic background which is more tolerable to the host plant especially upon secondary infection of highly aggressive, necrotrophic pathogens such as Fusarium graminearum. RESULTS BSMV-induced VIGS in Triticum aestivum (bread wheat) cv. 'Fielder' was assessed for the study of wheat genes putatively related to Fusarium Head Blight (FHB), the necrotrophism of wheat and other cereals by F. graminearum. Due to the lack of 'Fielder' spike viability and increased accumulation of Fusarium-derived deoxynivalenol contamination upon co-infection of BSMV and FHB, an attenuated BSMV construct was generated by the addition of a glycine-rich, C-terminal peptide to the BSMV γ b protein. This attenuated BSMV effectively silenced target wheat genes while limiting disease severity, deoxynivalenol contamination, and yield loss upon Fusarium co-infection compared to the original BSMV construct. The attenuated BSMV-infected tissue exhibited reduced abscisic, jasmonic, and salicylic acid defense phytohormone accumulation upon secondary Fusarium infection. Finally, the attenuated BSMV was used to investigate the role of the salicylic acid-responsive pathogenesis-related 1 in response to FHB. CONCLUSIONS The use of an attenuated BSMV may be advantageous in characterizing wheat genes involved in phytopathogenesis, including Fusarium necrotrophism, where minimal viral background effects on defense are required. Additionally, the attenuated BSMV elicits reduced defense hormone accumulation, suggesting that this genotype may have applications for the investigation of phytohormone-related signaling, developmental responses, and pathogen defense.
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Affiliation(s)
- Leann M. Buhrow
- />Aquatic and Crop Resources Development Portfolio, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Shawn M. Clark
- />Aquatic and Crop Resources Development Portfolio, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Michele C. Loewen
- />Aquatic and Crop Resources Development Portfolio, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
- />Department of Biochemistry, University of Saskatchewan, 107 Wiggins Rd., Saskatoon, SK S7N 5E5 Canada
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14
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Sun L, Andika IB, Kondo H, Chen J. Identification of the amino acid residues and domains in the cysteine-rich protein of Chinese wheat mosaic virus that are important for RNA silencing suppression and subcellular localization. MOLECULAR PLANT PATHOLOGY 2013; 14:265-78. [PMID: 23458485 PMCID: PMC6638639 DOI: 10.1111/mpp.12002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Cysteine-rich proteins (CRPs) encoded by some plant viruses in diverse genera function as RNA silencing suppressors. Within the N-terminal portion of CRPs encoded by furoviruses, there are six conserved cysteine residues and a Cys-Gly-X-X-His motif (Cys, cysteine; Gly, glycine; His, histidine; X, any amino acid residue) with unknown function. The central domains contain coiled-coil heptad amino acid repeats that usually mediate protein dimerization. Here, we present evidence that the conserved cysteine residues and Cys-Gly-X-X-His motif in the CRP of Chinese wheat mosaic virus (CWMV) are critical for protein stability and silencing suppression activity. Mutation of a leucine residue in the third coiled-coil heptad impaired CWMV CRP activity for suppression of local silencing, but not for the promotion of cell-to-cell movement of Potato virus X (PVX). In planta and in vitro analysis of wild-type and mutant proteins indicated that the ability of the CRP to self-interact was correlated with its suppression activity. Deletion of up to 40 amino acids at the C-terminus did not abolish suppression activity, but disrupted the association of CRP with endoplasmic reticulum (ER), and reduced its activity in the enhancement of PVX symptom severity. Interestingly, a short region in the C-terminal domain, predicted to form an amphipathic α-helical structure, was responsible for the association of CWMV CRP with ER. Overall, our results demonstrate that the N-terminal and central regions are the functional domains for suppression activity, whereas the C-terminal region primarily functions to target CWMV CRP to the ER.
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Affiliation(s)
- Liying Sun
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Ministry of Agriculture Key Laboratory of Biotechnology in Plant Protection, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
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15
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Lim HS, Lee MY, Moon JS, Moon JK, Yu YM, Cho IS, Bae H, deBoer M, Ju H, Hammond J, Jackson AO. Actin Cytoskeleton and Golgi Involvement in Barley stripe mosaic virus Movement and Cell Wall Localization of Triple Gene Block Proteins. THE PLANT PATHOLOGY JOURNAL 2013; 29:17-30. [PMID: 25288925 PMCID: PMC4174794 DOI: 10.5423/ppj.oa.09.2012.0144] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/08/2012] [Accepted: 10/10/2012] [Indexed: 05/29/2023]
Abstract
Barley stripe mosaic virus (BSMV) induces massive actin filament thickening at the infection front of infected Nicotiana benthamiana leaves. To determine the mechanisms leading to actin remodeling, fluorescent protein fusions of the BSMV triple gene block (TGB) proteins were coexpressed in cells with the actin marker DsRed: Talin. TGB ectopic expression experiments revealed that TGB3 is a major elicitor of filament thickening, that TGB2 resulted in formation of intermediate DsRed:Talin filaments, and that TGB1 alone had no obvious effects on actin filament structure. Latrunculin B (LatB) treatments retarded BSMV cell-to-cell movement, disrupted actin filament organization, and dramatically decreased the proportion of paired TGB3 foci appearing at the cell wall (CW). BSMV infection of transgenic plants tagged with GFP-KDEL exhibited membrane proliferation and vesicle formation that were especially evident around the nucleus. Similar membrane proliferation occurred in plants expressing TGB2 and/or TGB3, and DsRed: Talin fluorescence in these plants colocalized with the ER vesicles. TGB3 also associated with the Golgi apparatus and overlapped with cortical vesicles appearing at the cell periphery. Brefeldin A treatments disrupted Golgi and also altered vesicles at the CW, but failed to interfere with TGB CW localization. Our results indicate that actin cytoskeleton interactions are important in BSMV cell-to-cell movement and for CW localization of TGB3.
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Affiliation(s)
- Hyoun-Sub Lim
- Department of Applied Biology, Chungnam National University, Daejeon 305-764, Korea
| | - Mi Yeon Lee
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
| | - Jae Sun Moon
- Green Bio Research Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon 305-333, Korea
| | - Jung-Kyung Moon
- National Institute of Crop Science, Suwon, Rural Development Administration, 441-707, Korea
| | - Yong-Man Yu
- Department of Applied Biology, Chungnam National University, Daejeon 305-764, Korea
| | - In Sook Cho
- National Institute of Horticultural & Herbal Science, Rural Development Administration, Suwon 441-440, Korea
| | - Hanhong Bae
- School of Biotechnology, Yeungnam University, Gyeongsan, Korea
| | - Matt deBoer
- Virology Department, Wageningen University, 6709 PD Wageningen, The Netherlands
| | - Hojong Ju
- Department of Agricultural Biology, Chonbuk National University, Jeonju 561-756, Korea
| | - John Hammond
- USDA-ARS, US National Arboretum, Floral and Nursery Plants Research Unit, Beltsville, MD 20705 USA
| | - Andrew O. Jackson
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
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16
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Sun X, Zhang C. A conserved C-terminal motif is essential for self-interaction of Barley stripe mosaic virus China strain TGB3 protein. Biochem Biophys Res Commun 2012; 426:153-7. [PMID: 22925891 DOI: 10.1016/j.bbrc.2012.08.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 08/11/2012] [Indexed: 10/28/2022]
Abstract
The triple gene block (TGB) 3 protein is essential for the cell-to-cell movement of Barley stripe mosaic virus (BSMV). Previous studies have shown that TGB3, together with TGB2, facilitates the movement of TGB1 to the plasma membrane. However, the interactions among the three proteins (i.e., TGB3, TGB1, and TGB2) have not been thoroughly understood. The interactions of BSMV China strain (BSMV-CH) TGB3 with itself and with other two TGB proteins were investigated using a Gal4-based yeast two-hybrid system and pull-down assays. The results show that neither TGB1 nor TGB2 interacts with TGB3. However, self-interaction was detected for TGB3. The C-terminal 37 amino acids (amino acids 87-123) containing a conserved C-terminal motif were found required for the self-interaction of TGB3. The roles of the novel property of BSMV-CH TGB3 in virus cell-to-cell movement were discussed.
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Affiliation(s)
- Xianchao Sun
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing 400715, China.
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17
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Omarov RT, Scholthof HB. Biological chemistry of virus-encoded suppressors of RNA silencing: an overview. Methods Mol Biol 2012; 894:39-56. [PMID: 22678571 DOI: 10.1007/978-1-61779-882-5_3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
RNA interference (RNAi) plays multiple biological roles in eukaryotic organisms to regulate gene expression. RNAi also operates as a conserved adaptive molecular immune mechanism against invading viruses. The antiviral RNAi pathway is initiated with the generation of virus-derived short-interfering RNAs (siRNAs) that are used for subsequent sequence-specific recognition and degradation of the cognate viral RNA molecules. As an efficient counter-defensive strategy, most plant viruses evolved the ability to encode specific proteins capable of interfering with RNAi, and this process is commonly known as RNA silencing suppression. Virus-encoded suppressors of RNAi (VSRs) operate at different steps in the RNAi pathway and display distinct biochemical properties that enable these proteins to efficiently interfere with the host-defense system. Recent molecular and biochemical studies of several VSRs significantly expanded our understanding of the complex nature of silencing suppression, and also remarkably advanced our overall knowledge on complex host-virus interactions. In this review, we describe the current knowledge on activities and biochemical mechanisms of selected VSRs with regard to their biological role of suppressing RNAi in plants.
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Affiliation(s)
- Rustem T Omarov
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA
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18
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Verchot-Lubicz J, Torrance L, Solovyev AG, Morozov SY, Jackson AO, Gilmer D. Varied movement strategies employed by triple gene block-encoding viruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1231-47. [PMID: 20831404 DOI: 10.1094/mpmi-04-10-0086] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Several RNA virus genera belonging to the Virgaviridae and Flexiviridae families encode proteins organized in a triple gene block (TGB) that facilitate cell-to-cell and long-distance movement. The TGB proteins have been traditionally classified as hordei-like or potex-like based on phylogenetic comparisons and differences in movement mechanisms of the Hordeivirus and Potexvirus spp. However, accumulating data from other model viruses suggests that a revised framework is needed to accommodate the profound differences in protein interactions occurring during infection and ancillary capsid protein requirements for movement. The goal of this article is to highlight common features of the TGB proteins and salient differences in movement properties exhibited by individual viruses encoding these proteins. We discuss common and divergent aspects of the TGB transport machinery, describe putative nucleoprotein movement complexes, highlight recent data on TGB protein interactions and topological properties, and review membrane associations occurring during subcellular targeting and cell-to-cell movement. We conclude that the existing models cannot be used to explain all TGB viruses, and we propose provisional Potexvirus, Hordeivirus, and Pomovirus models. We also suggest areas that might profit from future research on viruses harboring this intriguing arrangement of movement proteins.
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Affiliation(s)
- Jeanmarie Verchot-Lubicz
- Oklahoma State University, Department of Entomology and Plant Pathology, Stillwater, OK 74078, USA.
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19
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Omarov RT, Bersimbai RI. Biochemical mechanisms of suppression of RNA interference by plant viruses. BIOCHEMISTRY. BIOKHIMIIA 2010; 75:965-970. [PMID: 21073416 DOI: 10.1134/s0006297910080031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
RNA interference (RNAi) plays an important biological role in regulation of gene expression of eukaryotes. In addition, RNAi was shown to be an adaptive protective molecular immune mechanism against viral diseases. Antiviral RNAi initiates from generation of short interfering RNAs used in the subsequent recognition and degradation of the viral RNA molecules. As a response to protective reaction of plants, most of the viruses encode specific proteins able to counteract RNAi. This process is known as RNAi suppression. Viral suppressors act on various stages of RNAi and have biochemical properties that enable viruses to effectively counteract the protective system of plants. Modern molecular and biochemical investigations of a number of viral suppressors have significantly expanded our understanding of the complexity of the nature of RNAi suppression as well as mechanisms of interaction between viruses and plants.
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Affiliation(s)
- R T Omarov
- Gumilev Eurasian National Institute, Astana, 10008, Kazakhstan.
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20
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Jackson AO, Lim HS, Bragg J, Ganesan U, Lee MY. Hordeivirus replication, movement, and pathogenesis. ANNUAL REVIEW OF PHYTOPATHOLOGY 2009; 47:385-422. [PMID: 19400645 DOI: 10.1146/annurev-phyto-080508-081733] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The last Hordeivirus review appearing in this series 20 years ago focused on the comparative biology, relationships, and genome organization of members of the genus ( 68 ). Prior to the 1989 review, useful findings about the origin, disease occurrence, host ranges, and general biological properties of Barley stripe mosaic virus (BSMV) were summarized in three comprehensive reviews ( 26, 67, 107 ). Several recent reviews emphasizing contemporary molecular genetic findings also may be of interest to various readers ( 15, 37, 42, 69, 70, 88, 113 ). In the current review, we briefly reiterate the biological properties of the four members of the Hordeivirus genus and describe advances in our understanding of organization and expression of the viral genomes. We also discuss the infection processes and pathogenesis of the most extensively characterized Hordeiviruses and frame these advances in the broader context of viruses in other families that have encoded triple gene block proteins. In addition, an overview of recent advances in the use of BSMV for virus-induced gene silencing is presented.
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Affiliation(s)
- Andrew O Jackson
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA.
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21
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Ghazala W, Waltermann A, Pilot R, Winter S, Varrelmann M. Functional characterization and subcellular localization of the 16K cysteine-rich suppressor of gene silencing protein of tobacco rattle virus. J Gen Virol 2008; 89:1748-1758. [PMID: 18559946 DOI: 10.1099/vir.0.83503-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
The 16 kDa cysteine-rich protein (16K) of tobacco rattle virus (TRV) is known to partially suppress RNA silencing in Drosophila cells. In this study, we show that 16K suppresses RNA silencing in green fluorescent protein (GFP)-transgenic Nicotiana benthamiana plants using an Agrobacterium-mediated transient assay. 16K slightly reduced the accumulation of short interfering RNAs (siRNA) of GFP, suggesting that the protein may interfere with the initiation and/or maintenance of RNA silencing. Deletion of either the N- or C-terminal part of 16K indicated that the entire 16K open reading frame (ORF) is necessary for its silencing suppression function. Pentapeptide insertion scanning mutagenesis (PSM) revealed that only two short regions of 16K tolerated five extra amino acid insertions without considerable reduction in its silencing suppression function. The tolerant regions coincide with sequence variability between tobravirus cysteine-rich proteins, indicating a strong functional and/or structural conservation of TRV 16K. Confocal laser scanning microscopy of transiently expressed 16K fusions to red fluorescent protein (RFP) revealed a predominant cytoplasmic localization and, in addition, a nuclear localization. In contrast, fusions of RFP with the N-terminal region of 16K localized exclusively to the cytoplasm, whereas fusions between RFP and the C-terminal region of 16K displayed an exclusive nuclear localization. Further analysis of 16K-derived peptide fusions demonstrated that the 16K C-terminal region contained at least two functional bipartite nuclear localization signals which were independently capable of nuclear targeting.
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Affiliation(s)
- Walid Ghazala
- Department of Crop Sciences, Section Plant Virology, Universität Göttingen, Grisebachstraße 6, D-37077 Göttingen, Germany
| | - Angelika Waltermann
- Institute of Plant Diseases and Plant Protection, Leibniz Universität Hannover, Herrenhaeuser Str. 2, D-30419 Hannover, Germany
| | - Ruth Pilot
- Department of Crop Sciences, Section Plant Virology, Universität Göttingen, Grisebachstraße 6, D-37077 Göttingen, Germany
| | - Stephan Winter
- Plant Virus Department, German Collection of Microorganisms and Cell Cultures (DSMZ), Mascheroder Weg 1b, D-38124 Braunschweig, Germany
| | - Mark Varrelmann
- Department of Crop Sciences, Section Plant Virology, Universität Göttingen, Grisebachstraße 6, D-37077 Göttingen, Germany
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22
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Rakitina DV, Yelina NE, Kalinina NO. Zinc ions stimulate the cooperative RNA binding of hordeiviral gammab protein. FEBS Lett 2006; 580:5077-83. [PMID: 16949581 DOI: 10.1016/j.febslet.2006.08.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 07/28/2006] [Accepted: 08/08/2006] [Indexed: 11/19/2022]
Abstract
A small regulatory gammab protein of the Poa semilatent hordeivirus (PSLV) contains two zinc finger-like motifs separated by a basic motif in the N-terminal part and a C-terminal coiled-coil motif. Interactions of the recombinant PSLV gammab protein and its mutants with various RNAs (ssRNA, dsRNA, ssRNA oligonucleotides) and ssDNA were studied in gel-shift assays. The results demonstrated that zinc ions are essential for effective nucleic-acid-binding activity of the gammab protein, suggesting the important role of zinc finger motifs in these interactions. Deletion of the C-proximal coiled-coil region did not affect highly cooperative RNA-protein binding, indicating that the N-terminal part of the protein contributes to the protein-protein interactions needed for the protein-RNA cooperativity.
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Affiliation(s)
- Daria V Rakitina
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
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23
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Mérai Z, Kerényi Z, Kertész S, Magna M, Lakatos L, Silhavy D. Double-stranded RNA binding may be a general plant RNA viral strategy to suppress RNA silencing. J Virol 2006; 80:5747-56. [PMID: 16731914 PMCID: PMC1472586 DOI: 10.1128/jvi.01963-05] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
In plants, RNA silencing (RNA interference) is an efficient antiviral system, and therefore successful virus infection requires suppression of silencing. Although many viral silencing suppressors have been identified, the molecular basis of silencing suppression is poorly understood. It is proposed that various suppressors inhibit RNA silencing by targeting different steps. However, as double-stranded RNAs (dsRNAs) play key roles in silencing, it was speculated that dsRNA binding might be a general silencing suppression strategy. Indeed, it was shown that the related aureusvirus P14 and tombusvirus P19 suppressors are dsRNA-binding proteins. Interestingly, P14 is a size-independent dsRNA-binding protein, while P19 binds only 21-nucleotide ds-sRNAs (small dsRNAs having 2-nucleotide 3' overhangs), the specificity determinant of the silencing system. Much evidence supports the idea that P19 inhibits silencing by sequestering silencing-generated viral ds-sRNAs. In this study we wanted to test the hypothesis that dsRNA binding is a general silencing suppression strategy. Here we show that many plant viral silencing suppressors bind dsRNAs. Beet yellows virus Peanut P21, clump virus P15, Barley stripe mosaic virus gammaB, and Tobacco etch virus HC-Pro, like P19, bind ds-sRNAs size-selectively, while Turnip crinkle virus CP is a size-independent dsRNA-binding protein, which binds long dsRNAs as well as ds-sRNAs. We propose that size-selective ds-sRNA-binding suppressors inhibit silencing by sequestering viral ds-sRNAs, whereas size-independent dsRNA-binding suppressors inactivate silencing by sequestering long dsRNA precursors of viral sRNAs and/or by binding ds-sRNAs. The findings that many unrelated silencing suppressors bind dsRNA suggest that dsRNA binding is a general silencing suppression strategy which has evolved independently many times.
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Affiliation(s)
- Zsuzsanna Mérai
- Agricultural Biotechnology Center, H-2101 Gödöllö, P. O. Box. 411, Hungary
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24
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Torrance L, Cowan GH, Gillespie T, Ziegler A, Lacomme C. Barley stripe mosaic virus-encoded proteins triple-gene block 2 and gammab localize to chloroplasts in virus-infected monocot and dicot plants, revealing hitherto-unknown roles in virus replication. J Gen Virol 2006; 87:2403-2411. [PMID: 16847137 DOI: 10.1099/vir.0.81975-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Replication of Barley stripe mosaic virus (BSMV), genus Hordeivirus, is thought to be associated with vesicles in proplastids and chloroplasts, but the molecular details of the process and identity of virus proteins involved in establishing the virus replication complexes are unknown. In addition, BSMV encodes a triple-gene block of movement proteins (TGBs) that putatively share functional roles with their counterparts in other hordei-, pomo- and pecluviruses, but detailed information on the intracellular locations of the individual TGBs is lacking. Here, the subcellular localizations of BSMV-encoded proteins TGB2 and gammab fused to green or red fluorescent proteins were examined in epidermal cells of Nicotiana benthamiana and barley (Hordeum vulgare 'Black Hulless'). The fusion proteins were expressed from a BSMV vector or under the control of the cauliflower mosaic virus 35S promoter. The subcellular localizations were studied by confocal laser-scanning microscopy (CLSM). CLSM studies showed that both proteins were recruited to chloroplasts in the presence of viral RNA and that virus RNA, coat protein and gammab protein were detected in plastid preparations from infected leaves. Electron microscope images of thin sections of virus-infected leaves revealed abnormal chloroplasts with cytoplasmic inclusions containing virus-like particles. In addition, cellular localizations of BSMV TGB2 suggest subtle differences in function between the hordei-like TGB2 proteins. The results indicate that TGB2 and gammab proteins play a previously unknown functional role at the site of virus replication.
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Affiliation(s)
- L Torrance
- Plant Pathology Programme, Scottish Crop Research Institute (SCRI), Invergowrie, Dundee DD2 5DA, UK
| | - G H Cowan
- Plant Pathology Programme, Scottish Crop Research Institute (SCRI), Invergowrie, Dundee DD2 5DA, UK
| | - T Gillespie
- Plant Pathology Programme, Scottish Crop Research Institute (SCRI), Invergowrie, Dundee DD2 5DA, UK
| | - A Ziegler
- Plant Pathology Programme, Scottish Crop Research Institute (SCRI), Invergowrie, Dundee DD2 5DA, UK
| | - C Lacomme
- Plant Pathology Programme, Scottish Crop Research Institute (SCRI), Invergowrie, Dundee DD2 5DA, UK
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25
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Sasaki N, Park JW, Maule AJ, Nelson RS. The cysteine–histidine-rich region of the movement protein of Cucumber mosaic virus contributes to plasmodesmal targeting, zinc binding and pathogenesis. Virology 2006; 349:396-408. [PMID: 16603215 DOI: 10.1016/j.virol.2006.02.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 12/13/2005] [Accepted: 02/15/2006] [Indexed: 11/18/2022]
Abstract
Viral movement proteins (MPs) are central to the establishment of viral pathogenesis, and yet relatively little is understood about the structural and functional aspects of MPs or about the host factors on which they depend. Through chemical mutagenesis of transgenic Arabidopsis expressing Cucumber mosaic virus (CMV) MP fused with the green fluorescent protein, we have studied the function of a central region of the MP, defined by a number of conserved cysteine and histidine residues (Cys-His-rich region), which potentially functions as a zinc-binding domain. Transient expression of mutant MPs identified through an in planta screen for altered MP function or constructed with altered putative zinc ligands through site-directed mutagenesis showed that mutations in the Cys-His-rich region affected localization to and trafficking through plasmodesmata. In vitro zinc-binding analysis revealed that wild type (wt) CMV MP had the ability to bind zinc and that movement-defective mutants bound zinc with less affinity than wt MP. Furthermore, a correlation between the association of the MP with plasmodesmata and virus pathogenesis was shown. We discuss roles of the Cys-His region in biochemical and biological functions of the MP during virus movement.
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Affiliation(s)
- Nobumitsu Sasaki
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., 2510 Sam Noble Parkway, Ardmore, OK 73402, USA
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26
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Xiao Z, Ehrlich E, Yu Y, Luo K, Wang T, Tian C, Yu XF. Assembly of HIV-1 Vif-Cul5 E3 ubiquitin ligase through a novel zinc-binding domain-stabilized hydrophobic interface in Vif. Virology 2006; 349:290-9. [PMID: 16530799 DOI: 10.1016/j.virol.2006.02.002] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 01/02/2006] [Accepted: 02/02/2006] [Indexed: 02/08/2023]
Abstract
APOBEC3G (A3G) and related cytidine deaminases are potent inhibitors of retroviruses. HIV-1 Vif hijacks the cellular Cul5-E3 ubiquitin ligase to degrade APOBEC3 proteins and render them ineffective against these viruses. Here, we report that HIV-1 Vif is a novel zinc-binding protein containing an H-x(5)-C-x(17-18)-C-x(3-5)-H motif that is distinct from other recognized classes of zinc fingers. Zinc-binding stabilized a conserved hydrophobic interface within the HCCH motif that is critical for Vif-Cul5 E3 assembly and Vif function. An N-terminal region in the first Cullin repeat of Cul5, which is dispensable for adaptor ElonginC binding, was required for interaction with Vif. This region is the most divergent sequence between Cul2 and Cul5, a factor that may contribute to the selection of Cul5 and not Cul2 by Vif. This is the first example of a zinc-binding substrate receptor responsible for the assembly of a Cullin-RING ligase, representing a new target for antiviral development.
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Affiliation(s)
- Zuoxiang Xiao
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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27
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Lukhovitskaya NI, Yelina NE, Zamyatnin AA, Schepetilnikov MV, Solovyev AG, Sandgren M, Morozov SY, Valkonen JPT, Savenkov EI. Expression, localization and effects on virulence of the cysteine-rich 8 kDa protein of Potato mop-top virus. J Gen Virol 2005; 86:2879-2889. [PMID: 16186244 DOI: 10.1099/vir.0.81099-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Potato mop-top virus (PMTV) RNA3 contains a triple gene block (TGB) encoding viral movement proteins and an open reading frame for a putative 8 kDa cysteine-rich protein (CRP). In this study, PMTV CRP was shown to be expressed in the course of virus infection, and a PMTV CRP-specific subgenomic RNA was mapped. CRP has previously been shown to be dispensable for infection of PMTV in Nicotiana benthamiana. In this study, PMTV CRP was found to increase the severity of disease symptoms when expressed from Potato virus X or Tobacco mosaic virus in N. benthamiana and Nicotiana tabacum, suggesting that the protein affects virulence of the virus or might suppress a host defence mechanism. However, PMTV CRP did not show RNA silencing suppression activity in three assays. Host responses to the PMTV CRP expression from different viral genomes ranged from an absence of response to extreme resistance at a single cell level and were dependent on the viral genome. These findings emphasized involvement of viral proteins and/or virus-induced cell components in the plant reaction to CRP. PMTV CRP was predicted to possess a transmembrane segment. CRP fused to the green fluorescent protein was associated with endoplasmic reticulum-derived membranes and induced dramatic rearrangements of the endoplasmic reticulum structure, which might account for protein functions as a virulence factor of the virus.
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Affiliation(s)
- N I Lukhovitskaya
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russian Federation
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), Box 7080, SE-750 07 Uppsala, Sweden
| | - N E Yelina
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), Box 7080, SE-750 07 Uppsala, Sweden
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russian Federation
| | - A A Zamyatnin
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), Box 7080, SE-750 07 Uppsala, Sweden
| | - M V Schepetilnikov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russian Federation
| | - A G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russian Federation
| | - M Sandgren
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), Box 7080, SE-750 07 Uppsala, Sweden
| | - S Yu Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russian Federation
| | - J P T Valkonen
- Department of Applied Biology, University of Helsinki, Finland
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), Box 7080, SE-750 07 Uppsala, Sweden
| | - E I Savenkov
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), Box 7080, SE-750 07 Uppsala, Sweden
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28
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29
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Te J, Melcher U, Howard A, Verchot-Lubicz J. Soilborne wheat mosaic virus (SBWMV) 19K protein belongs to a class of cysteine rich proteins that suppress RNA silencing. Virol J 2005; 2:18. [PMID: 15740624 PMCID: PMC555535 DOI: 10.1186/1743-422x-2-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Accepted: 03/01/2005] [Indexed: 11/10/2022] Open
Abstract
Amino acid sequence analyses indicate that the Soilborne wheat mosaic virus (SBWMV) 19K protein is a cysteine-rich protein (CRP) and shares sequence homology with CRPs derived from furo-, hordei-, peclu- and tobraviruses. Since the hordei- and pecluvirus CRPs were shown to be pathogenesis factors and/or suppressors of RNA silencing, experiments were conducted to determine if the SBWMV 19K CRP has similar activities. The SBWMV 19K CRP was introduced into the Potato virus X (PVX) viral vector and inoculated to tobacco plants. The SBWMV 19K CRP aggravated PVX-induced symptoms and restored green fluorescent protein (GFP) expression to GFP silenced tissues. These observations indicate that the SBWMV 19K CRP is a pathogenicity determinant and a suppressor of RNA silencing.
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Affiliation(s)
- Jeannie Te
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Ulrich Melcher
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Amanda Howard
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Jeanmarie Verchot-Lubicz
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
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30
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Zhang L, Wang Z, Wang X, Li D, Han C, Zhai Y, Yu J. Two virus-encoded RNA silencing suppressors, P14 ofBeet necrotic yellow vein virus and S6 ofRice black streak dwarf virus. ACTA ACUST UNITED AC 2005. [DOI: 10.1007/bf02897570] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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31
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Bragg JN, Jackson AO. The C-terminal region of the Barley stripe mosaic virusgammab protein participates in homologous interactions and is required for suppression of RNA silencing. MOLECULAR PLANT PATHOLOGY 2004; 5:465-481. [PMID: 20565621 DOI: 10.1111/j.1364-3703.2004.00246.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
SUMMARY The 17-kDa, cysteine-rich gammab protein of Barley stripe mosaic virus (BSMV) is a major contributor to viral pathogenesis, although it is dispensable for replication and movement in the ND 18 strain of the virus. Within the C-terminal region of gammab, six coiled-coil heptad repeats, structures known to mediate protein-protein interactions, are predicted between amino acids 95 and 140. In this study, we have demonstrated that gammab engages in homologous interactions and that the C-terminal 67 amino acids of the protein are required for these interactions. The gammab homologous interactions were abrogated by mutations designed to disrupt the coiled-coil motifs with substitutions of glycine residues for hydrophobic residues in the a and d positions of the heptads (gammabNC). Mutations within the gammabNC derivative were also found to destroy the silencing suppression activity of gammab in an Agrobacterium-mediated transient assay. Infectivity experiments to evaluate the gammabNC derivative revealed that this mutant developed symptoms 2 days earlier than the wild-type strain in Chenopodium amaranticolor. In barley, gammabNC elicited more severe bleaching and striping symptoms, similar to those of the previously described 'bleached' phenotype that is observed when mutations are introduced into the C1 and BM motifs. These findings collectively show that gammab interactions mediated by the coiled-coil motif are critical for the virulence and counter defence activities of BSMV in both monocot and dicot hosts.
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Affiliation(s)
- Jennifer N Bragg
- Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, CA 94720, USA
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