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Zhang K, Gu T, Xu X, Gan H, Qin L, Feng C, He Z. Sugarcane streak mosaic virus P1 protein inhibits unfolded protein response through direct suppression of bZIP60U splicing. PLoS Pathog 2023; 19:e1011738. [PMID: 37883577 PMCID: PMC10697598 DOI: 10.1371/journal.ppat.1011738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 12/05/2023] [Accepted: 10/04/2023] [Indexed: 10/28/2023] Open
Abstract
The unfolded protein response (UPR) is a cell-designated strategy that maintains the balance of protein folding in the endoplasmic reticulum (ER). UPR features a network of signal transduction pathways that reprogram the transcription, mRNA translation, and protein post-translational modification to relieve the ER stresses from unfolded/misfolded proteins. Infection with plant viruses can induce the UPR, and activated UPR often promotes plant viral infections in turn. However, the mechanism used by plant viruses to balance UPR and achieve robust infection remain largely unknown. In this study, P1SCSMV was identified as a virus-encoded RNA silencing suppressor (VSR). Heterologous overexpression of P1SCSMV via potato virus X (PVX) was found lead to programmed cell death (PCD) in Nicotiana benthamiana. Furthermore, P1SCSMV was also found to inhibit the PVX infection-triggered UPR by downregulating UPR-related genes and directly induced the distortion and collapse of the ER polygonal meshes on PVX-P1SCSMV infected N. benthamiana. Moreover, self-interaction, VSR activity, UPR inhibition, and cell death phenotype of P1SCSMV were also found to be dependent on its bipartite nuclear localization signal (NLS) (251RKRKLFPRIPLK262). P1SCSMV was found to directly bind to the stem-loop region of NbbZIP60U via its NLS and inhibit the UPR pathways, ultimately resulting in a PCD phenotype in PVX-P1SCSMV infected N. benthamiana leaves. This study also revealed the balancing role of potyviruses encoded P1SCSMV in the UPR pathway to achieve robust viral infection. This may represent a novel virulence strategy for plant viruses.
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Affiliation(s)
- Kun Zhang
- Department of Plant Pathology, College of Plant protection, Yangzhou University, Yangzhou, Jiangsu Province, P. R. China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, P. R. 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, P. R. China
| | - Tianxiao Gu
- Department of Plant Pathology, College of Plant protection, Yangzhou University, Yangzhou, Jiangsu Province, P. R. China
| | - Xiaowei Xu
- Department of Plant Pathology, College of Plant protection, Yangzhou University, Yangzhou, Jiangsu Province, P. R. China
| | - Haifeng Gan
- Department of Plant Pathology, College of Plant protection, Yangzhou University, Yangzhou, Jiangsu Province, P. R. China
| | - Lang Qin
- Department of Plant Pathology, College of Plant protection, Yangzhou University, Yangzhou, Jiangsu Province, P. R. China
| | - Chenwei Feng
- Department of Plant Pathology, College of Plant protection, Yangzhou University, Yangzhou, Jiangsu Province, P. R. China
| | - Zhen He
- Department of Plant Pathology, College of Plant protection, Yangzhou University, Yangzhou, Jiangsu Province, P. R. China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, P. R. China
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Kim H, Kawakubo S, Takahashi H, Masuta C. Two mutually exclusive evolutionary scenarios for allexiviruses that overcome host RNA silencing and autophagy by regulating viral CRP expression. PLoS Pathog 2023; 19:e1011457. [PMID: 37379324 DOI: 10.1371/journal.ppat.1011457] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 06/02/2023] [Indexed: 06/30/2023] Open
Abstract
The genus Allexivirus currently includes eight virus species that infect allium plants. Previously, we showed that there are two distinct groups of allexiviruses (deletion [D]-type and insertion [I]-type) based on the presence or absence of a 10- to 20-base insert (IS) between the coat protein (CP) and cysteine rich protein (CRP) genes. In the present study of CRPs to analyze their functions, we postulated that evolution of allexiviruses may have been largely directed by CRPs and thus proposed two evolutionary scenarios for allexiviruses based mainly on the presence or absence of IS and determined by how the allexiviruses challenge host resistance mechanisms (RNA silencing and autophagy). We found that both CP and CRP are RNA silencing suppressors (RSS), that they can inhibit each other's RSS activity in the cytoplasm, and that CRP becomes a target of host autophagy in the cytoplasm but not CP. To mitigate CRP interference with CP, and to increase the CP's RSS activity, allexiviruses developed two strategies: confinement of D-type CRP in the nucleus and degradation of I-type CRP by autophagy in the cytoplasm. Here, we demonstrate that viruses of the same genus achieve two completely different evolutionary scenarios by controlling expression and subcellular localization of CRP.
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Affiliation(s)
- Hangil Kim
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, Japan
| | - Shusuke Kawakubo
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, Japan
| | - Haruna Takahashi
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, Japan
| | - Chikara Masuta
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, Japan
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Tatineni S, Alexander J, Nunna H. 6K1, NIa-VPg, NIa-Pro, and CP of Wheat Streak Mosaic Virus Are Collective Determinants of Wheat Streak Mosaic Disease in Wheat. PHYTOPATHOLOGY 2023; 113:1115-1127. [PMID: 36537846 DOI: 10.1094/phyto-10-22-0401-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Wheat streak mosaic virus (WSMV; genus Tritimovirus, family Potyviridae) is the causal agent of the most economically important wheat streak mosaic disease of wheat (Triticum aestivum) in the Great Plains region of the United States. WSMV determinants responsible for wheat streak mosaic disease in wheat are unknown. Triticum mosaic virus (TriMV), a wheat-infecting virus, was used as an expression vector for the transient expression of each of the WSMV-encoded cistrons in wheat. WSMV-encoded 6K1, NIa-VPg, NIa-Pro, and CP cistrons in TriMV elicited symptoms specific to different stages of wheat streak mosaic disease without significantly affecting the genomic RNA accumulation. WSMV 6K1 produced early wheat streak mosaic disease-like symptoms of severe chlorotic streaks and patches. NIa-VPg and CP caused severe chlorotic streaks, followed by moderate stunting (only with NIa-VPg) of wheat, mimicking early- and mid-stage symptoms of wheat streak mosaic disease. WSMV NIa-Pro caused mild chlorotic streaks, followed by dark green leaves with severe stunting, representing the late symptoms of wheat streak mosaic disease. Collectively, these data suggest that cumulative effects of WSMV-encoded 6K1, NIa-VPg, NIa-Pro, and CP are responsible for different stages of wheat streak mosaic disease symptoms in wheat. Furthermore, deletion analysis of wheat streak mosaic disease determinants revealed that complete 6K1 and NIa-Pro, amino acids 3 to 60 and 121 to 197 of NIa-VPg, and amino acids 101 to 294 of CP are responsible for wheat streak mosaic disease-like symptoms in wheat. This study suggests that management strategies for wheat streak mosaic disease in wheat should target WSMV determinants of the disease phenotype.
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Affiliation(s)
- Satyanarayana Tatineni
- U.S. Department of Agriculture-Agricultural Research Service, University of Nebraska-Lincoln, Lincoln, NE 68583
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68503
| | - Jeffrey Alexander
- U.S. Department of Agriculture-Agricultural Research Service, University of Nebraska-Lincoln, Lincoln, NE 68583
| | - Haritha Nunna
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68503
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Zhang K, Xu X, Guo X, Ding S, Gu T, Qin L, He Z. Sugarcane Streak Mosaic Virus P1 Attenuates Plant Antiviral Immunity and Enhances Potato Virus X Infection in Nicotiana benthamiana. Cells 2022; 11:cells11182870. [PMID: 36139443 PMCID: PMC9497147 DOI: 10.3390/cells11182870] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/06/2022] [Accepted: 09/10/2022] [Indexed: 12/05/2022] Open
Abstract
The sugarcane streak mosaic virus (SCSMV) is the most important disease in sugarcane produced in southern China. The SCSMV encoded protein 1 (P1SCSMV) is important in disease development, but little is known about its detailed functions in plant–virus interactions. Here, the differential accumulated proteins (DAPs) were identified in the heterologous expression of P1SCSMV via a potato virus X (PVX)-based expression system, using a newly developed four-dimensional proteomics approach. The data were evaluated for credibility and reliability using qRT-RCR and Western blot analyses. The physiological response caused by host factors that directly interacted with the PVX-encoded proteins was more pronounced for enhancing the PVX accumulation and pathogenesis in Nicotiana benthamiana. P1SCSMV reduced photosynthesis by damaging the photosystem II (PSII). Overall, P1SCSMV promotes changes in the physiological status of its host by up- or downregulating the expression of host factors that directly interact with the viral proteins. This creates optimal conditions for PVX replication and movement, thereby enhancing its accumulation levels and pathogenesis. Our investigation is the first to supply detailed evidence of the pathogenesis-enhancing role of P1SCSMV, which provides a deeper understanding of the mechanisms behind virus–host interactions.
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Affiliation(s)
- Kun Zhang
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, 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 210023, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Xiaowei Xu
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Xiao Guo
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Shiwen Ding
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Tianxiao Gu
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Lang Qin
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Zhen He
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
- Correspondence: ; Tel.: +86-1529-8450-157
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Pasin F, Daròs JA, Tzanetakis IE. OUP accepted manuscript. FEMS Microbiol Rev 2022; 46:6534904. [PMID: 35195244 PMCID: PMC9249622 DOI: 10.1093/femsre/fuac011] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 02/02/2022] [Accepted: 02/08/2022] [Indexed: 11/17/2022] Open
Abstract
Potyviridae, the largest family of known RNA viruses (realm Riboviria), belongs to the picorna-like supergroup and has important agricultural and ecological impacts. Potyvirid genomes are translated into polyproteins, which are in turn hydrolyzed to release mature products. Recent sequencing efforts revealed an unprecedented number of potyvirids with a rich variability in gene content and genomic layouts. Here, we review the heterogeneity of non-core modules that expand the structural and functional diversity of the potyvirid proteomes. We provide a family-wide classification of P1 proteinases into the functional Types A and B, and discuss pretty interesting sweet potato potyviral ORF (PISPO), putative zinc fingers, and alkylation B (AlkB)—non-core modules found within P1 cistrons. The atypical inosine triphosphate pyrophosphatase (ITPase/HAM1), as well as the pseudo tobacco mosaic virus-like coat protein (TMV-like CP) are discussed alongside homologs of unrelated virus taxa. Family-wide abundance of the multitasking helper component proteinase (HC-pro) is revised. Functional connections between non-core modules are highlighted to support host niche adaptation and immune evasion as main drivers of the Potyviridae evolutionary radiation. Potential biotechnological and synthetic biology applications of potyvirid leader proteinases and non-core modules are finally explored.
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Affiliation(s)
- Fabio Pasin
- Corresponding author: Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València (CSIC-UPV), UPV Building 8E, Ingeniero Fausto Elio, 46011 Valencia, Spain. E-mail:
| | - José-Antonio Daròs
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València (CSIC-UPV), 46011 Valencia, Spain
| | - Ioannis E Tzanetakis
- Department of Entomology and Plant Pathology, Division of Agriculture, University of Arkansas System, 72701 Fayetteville, AR, USA
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García B, Bedoya L, García JA, Rodamilans B. An Importin-β-like Protein from Nicotiana benthamiana Interacts with the RNA Silencing Suppressor P1b of the Cucumber Vein Yellowing Virus, Modulating Its Activity. Viruses 2021; 13:2406. [PMID: 34960675 PMCID: PMC8706682 DOI: 10.3390/v13122406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 11/26/2022] Open
Abstract
During a plant viral infection, host-pathogen interactions are critical for successful replication and propagation of the virus through the plant. RNA silencing suppressors (RSSs) are key players of this interplay, and they often interact with different host proteins, developing multiple functions. In the Potyviridae family, viruses produce two main RSSs, HCPro and type B P1 proteins. We focused our efforts on the less known P1b of cucumber vein yellowing virus (CVYV), a type B P1 protein, to try to identify possible factors that could play a relevant role during viral infection. We used a chimeric expression system based on plum pox virus (PPV) encoding a tagged CVYV P1b in place of the canonical HCPro. We used that tag to purify P1b in Nicotiana-benthamiana-infected plants and identified by mass spectrometry an importin-β-like protein similar to importin 7 of Arabidopsis thaliana. We further confirmed the interaction by bimolecular fluorescence complementation assays and defined its nuclear localization in the cell. Further analyses showed a possible role of this N. benthamiana homolog of Importin 7 as a modulator of the RNA silencing suppression activity of P1b.
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Affiliation(s)
| | | | | | - Bernardo Rodamilans
- Centro Nacional de Biotecnología CNB, Consejo Superior de Investigaciones Científicas CSIC, 28049 Madrid, Spain; (B.G.); (L.B.); (J.A.G.)
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Gupta AK, Hein GL, Tatineni S. P7 and P8 proteins of High Plains wheat mosaic virus, a negative-strand RNA virus, employ distinct mechanisms of RNA silencing suppression. Virology 2019; 535:20-31. [PMID: 31254744 DOI: 10.1016/j.virol.2019.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 06/14/2019] [Accepted: 06/16/2019] [Indexed: 10/26/2022]
Abstract
High Plains wheat mosaic virus (genus Emaravirus), an octapartite negative-sense RNA virus, encodes two RNA silencing suppressors, P7 and P8. In this study, we found that P7 and P8 efficiently delayed the onset of dsRNA-induced transitive pathway of RNA silencing. Electrophoretic mobility shift assays (EMSA) revealed that only P7 protected long dsRNAs from dicing in vitro and bound weakly to 21- and 24-nt PTGS-like ds-siRNAs. In contrast, P8 bound strongly and relatively weakly to 21- and 24-nt ds-siRNAs, respectively, suggesting size-specific binding. In EMSA, neither protein bound to 180-nt and 21-nt ssRNAs at detectable levels. Sequence analysis revealed that P7 contains a conserved GW motif. Mutational disruption of this motif resulted in loss of suppression of RNA silencing and pathogenicity enhancement, and failure to complement the silencing suppression-deficient wheat streak mosaic virus. Collectively, these data suggest that P7 and P8 proteins utilize distinct mechanisms to overcome host RNA silencing for successful establishment of systemic infection in planta.
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Affiliation(s)
- Adarsh K Gupta
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Gary L Hein
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Satyanarayana Tatineni
- United States Department of Agriculture-Agricultural Research Service and Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA.
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