scholarly journals Deciphering the RNA Silencing Suppressor Function in the Potyvirus SPV2

Proceedings ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 26
Author(s):  
Ornela Chase ◽  
Giannina Bambaren ◽  
Juan José López-Moya
Keyword(s):  
Rna Silencing ◽  
Ipomoea Batatas ◽  
Control Strategies ◽  
Regulation Of Gene Expression ◽  
Plant Viruses ◽  
High Yield ◽  
Gene Products ◽  
Silencing Suppressor ◽  
Sweet Potatoes ◽  
Rna Silencing Suppressor

In most eukaryotes, RNA silencing is a key element in the regulation of gene expression and defense against pathogens. Plants have developed a defensive barrier against exogenous microorganisms, such as plant-infecting viruses, by specifically targeting and degrading the viral RNAs and thus limiting the negative effects of the diseases caused by them. On the other hand, plant viruses encode for suppressor proteins that repress the host-silencing machinery, hence allowing viral replication and infection establishment. Our current project focuses on the characterization of gene products contributing to the RNA silencing suppressor (RSS) function of Sweet potato virus 2 (SPV2), genus Potyvirus, family Potyviridae. SPV2 infects sweet potatoes (Ipomoea batatas, family Convolvulaceae), one of the most important staple food crops worldwide. Infections by potyvirids result in the high yield losses of sweet potatoes, especially from coinfection with unrelated viruses, and our final goal is to develop efficient control strategies. Our preliminary results analyzing the P1 and HCPro proteases of SPV2, transiently expressed in N. benthamiana together with a reporter GFP construct, revealed that HCPro constitutes a strong RSS. This is a novel finding, and we are currently characterizing the functions of other gene products.

scholarly journals The P1N-PISPOtrans-Frame Gene of Sweet Potato Feathery Mottle Potyvirus Is Produced during Virus Infection and Functions as an RNA Silencing Suppressor

2016 ◽  
Vol 90 (7) ◽  
pp. 3543-3557 ◽  
Author(s):  
Ares Mingot ◽  
Adrián Valli ◽  
Bernardo Rodamilans ◽  
David San León ◽  
David C. Baulcombe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Sweet Potato ◽  
Rna Silencing ◽  
Mottle Virus ◽  
Gene Products ◽  
Silencing Suppressor ◽  
Content Type ◽  
Rna Silencing Suppressor ◽  
Silencing Suppression ◽  
Polymerase Slippage

ABSTRACTThe positive-sense RNA genome ofSweet potato feathery mottle virus(SPFMV) (genusPotyvirus, familyPotyviridae) contains a large open reading frame (ORF) of 3,494 codons translatable as a polyprotein and two embedded shorter ORFs in the −1 frame: PISPO, of 230 codons, and PIPO, of 66 codons, located in the P1 and P3 regions, respectively. PISPO is specific to some sweet potato-infecting potyviruses, while PIPO is present in all potyvirids. In SPFMV these two extra ORFs are preceded by conserved G2A6motifs. We have shown recently that a polymerase slippage mechanism at these sites could produce transcripts bringing these ORFs in frame with the upstream polyprotein, thus leading to P1N-PISPO and P3N-PIPO products (B. Rodamilans, A. Valli, A. Mingot, D. San Leon, D. B. Baulcombe, J. J. Lopez-Moya, and J.A. Garcia, J Virol 89:6965–6967, 2015, doi:10.1128/JVI.00337-15). Here, we demonstrate by liquid chromatography coupled to mass spectrometry that both P1 and P1N-PISPO are produced during viral infection and coexist in SPFMV-infectedIpomoea batatasplants. Interestingly, transient expression of SPFMV gene products coagroinfiltrated with a reporter gene inNicotiana benthamianarevealed that P1N-PISPO acts as an RNA silencing suppressor, a role normally associated with HCPro in other potyviruses. Moreover, mutation of WG/GW motifs present in P1N-PISPO abolished its silencing suppression activity, suggesting that the function might require interaction with Argonaute components of the silencing machinery, as was shown for other viral suppressors. Altogether, our results reveal a further layer of complexity of the RNA silencing suppression activity within thePotyviridaefamily.IMPORTANCEGene products of potyviruses include P1, HCPro, P3, 6K1, CI, 6K2, VPg/NIaPro, NIb, and CP, all derived from the proteolytic processing of a large polyprotein, and an additional P3N-PIPO product, with the PIPO segment encoded in a different frame within the P3 cistron. In sweet potato feathery mottle virus (SPFMV), another out-of-frame element (PISPO) was predicted within the P1 region. We have shown recently that a polymerase slippage mechanism can generate the transcript variants with extra nucleotides that could be translated into P1N-PISPO and P3N-PIPO. Now, we demonstrate by mass spectrometry analysis that P1N-PISPO is indeed produced in SPFMV-infected plants, in addition to P1. Interestingly, while in other potyviruses the suppressor of RNA silencing is HCPro, we show here that P1N-PISPO exhibited this activity in SPFMV, revealing how the complexity of the gene content could contribute to supply this essential function in members of thePotyviridaefamily.

scholarly journals The Coat Protein of Citrus Yellow Vein Clearing Virus Interacts with Viral Movement Proteins and Serves as an RNA Silencing Suppressor

Viruses ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 329 ◽  
Author(s):  
Atta Ur Rehman ◽  
Zhuoran Li ◽  
Zuokun Yang ◽  
Muhammad Waqas ◽  
Guoping Wang ◽  
...  
Keyword(s):  
Coat Protein ◽  
Rna Silencing ◽  
Triple Gene Block ◽  
Plant Viruses ◽  
Epidermal Cells ◽  
Yellow Vein ◽  
Silencing Suppressor ◽  
Vein Clearing ◽  
Rna Silencing Suppressor ◽  
Viral Movement

Citrus yellow vein clearing virus is a newly accepted member of the genus Mandarivirus in the family Alphaflexiviridae. The triple gene block proteins (TGBp1, TGBp2 and TGBp3) encoded by plant viruses in this family function on facilitating virus movement. However, the protein function of citrus yellow vein clearing virus (CYVCV) have never been explored. Here, we showed in both yeast two-hybrid (Y2H) and bimolecular fluorescence (BiFC) assays that the coat protein (CP), TGBp1 and TGBp2 of CYVCV are self-interacting. Its CP also interacts with all three TGB proteins, and TGBp1 and TGBp2 interact with each other but not with TGBp3. Furthermore, the viral CP colocalizes with TGBp1 and TGBp3 at the plasmodesmata (PD) of epidermal cells of Nicotiana benthamiana leaves, and TGBp1 can translocate TGBp2 from granular-like structures embedded within ER networks to the PD. The results suggest that these proteins could coexist at the PD of epidermal cells of N. benthamiana. Using Agrobacterium infiltration-mediated RNA silencing assays, we show that CYVCV CP is a strong RNA silencing suppressor (RSS) triggered by positive-sense green fluorescent protein (GFP) RNA. The presented results provide insights for further revealing the mechanism of the viral movement and suppression of RNA silencing.

scholarly journals Identification of the Potential Virulence Factors and RNA Silencing Suppressors of Mulberry Mosaic Dwarf-Associated Geminivirus

Viruses ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 472 ◽  
Author(s):  
Xiuling Yang ◽  
Yanxiang Ren ◽  
Shaoshuang Sun ◽  
Dongxue Wang ◽  
Fanfan Zhang ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Rna Silencing ◽  
Fluorescent Protein ◽  
Potato Virus X ◽  
Defense Responses ◽  
Plant Viruses ◽  
Silencing Suppressor ◽  
Long Distance ◽  
Suppressor Activity ◽  
Rna Silencing Suppressor

Plant viruses encode virulence factors or RNA silencing suppressors to reprogram plant cellular processes or to fine-tune host RNA silencing-mediated defense responses. In a previous study, Mulberry mosaic dwarf-associated virus (MMDaV), a novel, highly divergent geminivirus, has been identified from a Chinese mulberry tree showing mosaic and dwarfing symptoms, but the functions of its encoded proteins are unknown. In this study, all seven proteins encoded by MMDaV were screened for potential virulence and RNA silencing suppressor activities. We found that V2, RepA, and Rep affect the pathogenicity of a heterologous potato virus X. We showed that V2 could inhibit local RNA silencing and long-distance movement of the RNA silencing signal, but not short-range spread of the green fluorescent protein (GFP) silencing signal in Nicotiana benthamiana 16c plants. In addition, V2 localized to both subnuclear foci and the cytoplasm. Deletion mutagenesis of V2 showed that the basic motif from amino acids 61 to 76 was crucial for V2 to form subnuclear foci and for suppression of RNA silencing. Although the V2 protein encoded by begomoviruses or a curtovirus has been shown to have silencing suppressor activity, this is the first identification of an RNA silencing suppressor from a woody plant-infecting geminivirus.

RNA Silencing Suppressor p19 Regulates The Expressions of Cell Cycle Related Genes*

2009 ◽  
Vol 36 (5) ◽  
pp. 541-548 ◽  
Author(s):  
Li LIU ◽  
Jian LI ◽  
Yu-Ping XU ◽  
Wen-Tao QIAO ◽  
Qi-Min CHEN ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Rna Silencing ◽  
Silencing Suppressor ◽  
Rna Silencing Suppressor

Identification of RNA silencing suppressor encoded by wheat blue dwarf (WBD) phytoplasma

Plant Biology ◽  
2021 ◽  
Author(s):  
Licheng Wang ◽  
Wenbao Chen ◽  
Huan Ma ◽  
Jingyuan Li ◽  
Xingan Hao ◽  
...  
Keyword(s):  
Rna Silencing ◽  
Silencing Suppressor ◽  
Rna Silencing Suppressor

scholarly journals Identification and subcellular location of an RNA silencing suppressor encoded by mulberry crinkle leaf virus

Virology ◽  
2019 ◽  
Vol 526 ◽  
pp. 45-51 ◽  
Author(s):  
Quan-You Lu ◽  
Lei Yang ◽  
Jinshan Huang ◽  
Luping Zheng ◽  
Xin Sun
Keyword(s):  
Rna Silencing ◽  
Subcellular Location ◽  
Silencing Suppressor ◽  
Rna Silencing Suppressor ◽  
Leaf Virus

scholarly journals Rapid screening of RNA silencing suppressors by using a recombinant virus derived from beet necrotic yellow vein virus

2009 ◽  
Vol 90 (10) ◽  
pp. 2536-2541 ◽  
Author(s):  
H. Guilley ◽  
D. Bortolamiol ◽  
G. Jonard ◽  
S. Bouzoubaa ◽  
V. Ziegler-Graff
Keyword(s):  
Rna Silencing ◽  
Plant Defence ◽  
Plant Viruses ◽  
Yellow Vein ◽  
Rapid Screening ◽  
Silencing Suppressor ◽  
Defence Mechanisms ◽  
Simple Method ◽  
Yellow Dwarf Virus ◽  
Plant Defence Mechanisms

To counteract plant defence mechanisms, plant viruses have evolved to encode RNA silencing suppressor (RSS) proteins. These proteins can be identified by a range of silencing suppressor assays. Here, we describe a simple method using beet necrotic yellow vein virus (BNYVV) that allows a rapid screening of RSS activity. The viral inoculum consisted of BNYVV RNA1, which encodes proteins involved in viral replication, and two BNYVV-derived replicons: rep3–P30, which expresses the movement protein P30 of tobacco mosaic virus, and rep5–X, which allows the expression of a putative RSS (X). This approach has been validated through the use of several known RSSs. Two potential candidates have been tested and we show that, in our system, the P13 protein of burdock mottle virus displays RSS activity while the P0 protein of cereal yellow dwarf virus-RPV does not.

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