scholarly journals Genetic Analyses of the FRNK Motif Function of Turnip mosaic virus Uncover Multiple and Potentially Interactive Pathways of Cross-Protection

2014 ◽  
Vol 27 (9) ◽  
pp. 944-955 ◽  
Author(s):  
Yi-Jung Kung ◽  
Pin-Chun Lin ◽  
Shyi-Dong Yeh ◽  
Syuan-Fei Hong ◽  
Nam-Hai Chua ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
Turnip Mosaic Virus ◽  
Cross Protection ◽  
Mild Strain ◽  
Silencing Suppression ◽  
Helper Component Proteinase ◽  
Silencing Pathways ◽  
Protection Against Infection

Cross-protection triggered by a mild strain of virus acts as a prophylaxis to prevent subsequent infections by related viruses in plants; however, the underling mechanisms are not fully understood. Through mutagenesis, we isolated a mutant strain of Turnip mosaic virus (TuMV), named Tu-GK, that contains an Arg182Lys substitution in helper component-proteinase (HC-ProK) that confers complete cross-protection against infection by a severe strain of TuMV in Nicotiana benthamiana, Arabidopsis thaliana Col-0, and the Arabidopsis dcl2-4/dcl4-1 double mutant defective in DICER-like ribonuclease (DCL)2/DCL4-mediated silencing. Our analyses showed that HC-ProK loses the ability to interfere with microRNA pathways, although it retains a partial capability for RNA silencing suppression triggered by DCL. We further showed that Tu-GK infection triggers strong salicylic acid (SA)-dependent and SA-independent innate immunity responses. Our data suggest that DCL2/4-dependent and –independent RNA silencing pathways are involved, and may crosstalk with basal innate immunity pathways, in host defense and in cross-protection.

Comparison of helper component-protease RNA silencing suppression activity, subcellular localization, and aggregation of three Korean isolates of Turnip mosaic virus

Virus Genes ◽  
2016 ◽  
Vol 52 (4) ◽  
pp. 592-596 ◽  
Author(s):  
Jae-Yeong Han ◽  
Jinsoo Chung ◽  
Jungkyu Kim ◽  
Eun-Young Seo ◽  
James P. Kilcrease ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
Turnip Mosaic Virus ◽  
Helper Component ◽  
Silencing Suppression

scholarly journals Rice Stripe Mosaic Virus–Encoded P4 Is a Weak Suppressor of Viral RNA Silencing and Is Required for Disease Symptom Development

2020 ◽  
Vol 33 (3) ◽  
pp. 412-422
Author(s):  
Chao Zhang ◽  
Dong Chen ◽  
Guoyi Yang ◽  
Xiyuan Yu ◽  
Jianguo Wu
Keyword(s):  
Mosaic Virus ◽  
Rna Silencing ◽  
Matrix Protein ◽  
Expression System ◽  
Potato Virus X ◽  
Bimolecular Fluorescence Complementation ◽  
Developmental Defects ◽  
The Matrix ◽  
Silencing Pathways ◽  
Viral Suppressors

Viral suppressors of RNA silencing (VSRs) are a cluster of viral proteins that have evolved to counteract eukaryotic antiviral RNA silencing pathways, thereby contributing to viral pathogenicity. In this study, we revealed that the matrix protein P4 encoded by rice stripe mosaic virus (RSMV), which is an emerging cytoplasmic rhabdovirus, is a weak RNA silencing suppressor. By conducting yeast two-hybrid, bimolecular fluorescence complementation, and subcellular colocalization assays, we proved that P4 interacts with the rice endogenous suppressor of gene silencing 3 (OsSGS3). We also determined that P4 overexpression has no effect on OsSGS3 transcription. However, P4 can promote the degradation of OsSGS3 via ubiquitination and autophagy. Additionally, a potato virus X–based expression system was used to confirm that P4 enhances the development of mosaic symptoms on Nicotiana benthamiana leaves by promoting hydrogen peroxide accumulation but not cell death. To verify whether P4 is a pathogenicity factor in host plants, we generated transgenic P4-overexpressing rice plants that exhibited disease-related developmental defects including decreased plant height and excessive tillering. Our data suggest that RSMV-encoded P4 serves as a weak VSR that inhibits antiviral RNA silencing by targeting OsSGS3.

scholarly journals A Single Amino Acid Mutation in the Plum pox virus Helper Component-Proteinase Gene Abolishes Both Synergistic and RNA Silencing Suppression Activities

2005 ◽  
Vol 95 (8) ◽  
pp. 894-901 ◽  
Author(s):  
Pablo González-Jara ◽  
Felix A. Atencio ◽  
Belén Martínez-García ◽  
Daniel Barajas ◽  
Francisco Tenllado ◽  
...  
Keyword(s):  
Amino Acid ◽  
Point Mutation ◽  
Rna Silencing ◽  
Recombinant Virus ◽  
Single Amino Acid ◽  
Single Point Mutation ◽  
Plum Pox Virus ◽  
Helper Component ◽  
Silencing Suppression ◽  
Helper Component Proteinase

The effects on symptom expression of single amino acid mutations in the central region of the Plum pox virus (PPV) helper component-proteinase (HC-Pro) gene were analyzed in Nicotiana benthamiana using Potato virus X (PVX) recombinant viruses. PVX recombinant virus expressing the wild-type variant of PPV HC-Pro induced the expected enhancement of PVX pathogenicity, manifested as necrosis and plant death. Recombinant virus expressing a variant of PPV HC-Pro containing a single point mutation ( HCL134H) was unable to induce this synergistic phenotype. The RNA silencing suppressor activity of PPV HC-Pro was demonstrated in a transient silencing suppression assay. In contrast, the HCL134H mutant showed no such activity. These results indicate that a unique point mutation in PPV HC-Pro impaired its ability to suppress RNA silencing and abolished its capacity to induce synergism, and clearly shows for the first time the link between these two functions in potyvirus HC-Pro. Additionally, we compared the effects on virus accumulation in N. benthamiana plants infected with either the PVX recombinant constructs or with native viruses in double infection experiments. PVX (+) and (-) strand genomic RNA accumulated at similar levels in plants infected with PVX recombinants, leading to an increase in PVX pathology, compared with plants infected with PVX alone. This finding confirms that the enhancement of pathogenicity associated with synergistic interaction is not a consequence of more efficient PVX replication due to RNA silencing suppression by PPV HC-Pro.

scholarly journals Symptom induction and RNA silencing suppression by the cucumber mosaic virus 2b protein

2010 ◽  
Vol 5 (6) ◽  
pp. 705-708 ◽  
Author(s):  
Mathew G. Lewsey ◽  
Inmaculada González ◽  
Natalia O. Kalinina ◽  
Peter Palukaitis ◽  
Tomas Canto ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
2B Protein ◽  
Silencing Suppression

scholarly journals Multiple Domains of the Tobacco mosaic virus p126 Protein Can Independently Suppress Local and Systemic RNA Silencing

2012 ◽  
Vol 25 (5) ◽  
pp. 648-657 ◽  
Author(s):  
Li-Ya Wang ◽  
Shih-Shun Lin ◽  
Ting-Hsuan Hung ◽  
Tsai-Kun Li ◽  
Nai-Chun Lin ◽  
...  
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
Large Size ◽  
Silencing Suppression ◽  
Systemic Rna ◽  
Multiple Domains ◽  
Region Ii ◽  
Suppressor Of Rna Silencing ◽  
Antiviral Mechanism

Small RNA-mediated RNA silencing is a widespread antiviral mechanism in plants and other organisms. Many viruses encode suppressors of RNA silencing for counter-defense. The p126 protein encoded by Tobacco mosaic virus (TMV) has been reported to be a suppressor of RNA silencing but the mechanism of its function remains unclear. This protein is unique among the known plant viral silencing suppressors because of its large size and multiple domains. Here, we report that the methyltransferase, helicase, and nonconserved region II (NONII) of p126 each has silencing-suppressor function. The silencing-suppression activities of methyltransferase and helicase can be uncoupled from their enzyme activities. Specific amino acids in NONII previously shown to be crucial for viral accumulation and symptom development are also crucial for silencing suppression. These results suggest that some viral proteins have evolved to possess modular structural domains that can independently interfere with host silencing, and that this may be an effective mechanism of increasing the robustness of a virus.

scholarly journals A Double Mutation in the Conserved Motifs of the Helper Component Protease of Papaya Leaf Distortion Mosaic Virus for the Generation of a Cross-Protective Attenuated Strain

2020 ◽  
Vol 110 (1) ◽  
pp. 187-193 ◽  
Author(s):  
Decai Tuo ◽  
Peng Zhou ◽  
Guangyuan Zhao ◽  
Pu Yan ◽  
Dong Tan ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Carica Papaya ◽  
Cross Protection ◽  
Symptom Expression ◽  
Plant Growth And Development ◽  
Effective Protection ◽  
Mild Strain ◽  
Double Mutation ◽  
Helper Component ◽  
Leaf Distortion

Potyviral helper component protease (HC-Pro), as a major determinant of symptom expression in susceptible plants, is a likely target candidate in the production of attenuated strains for cross-protection. In this study, single or double mutations of Lys (K) to Glu (E) in the Lys-Ile-Thr-Cys motif and Arg (R) to Ile (I) in the Phe-Arg-Asn-Lys motif of the HC-Pro from the severe papaya leaf distortion mosaic virus strain DF (PLDMV-DF) reduced symptom expression and virus accumulation in infected papaya (Carica papaya) plants. The papaya plants infected with the attenuated double mutant of PLDMV-EI presented as symptomless. PLDMV-EI provided effective protection against PLDMV-DF infection in three papaya cultivars and had no effect on plant growth and development. Our result showed that PLDMV-EI is a promising mild strain for the practical use of cross-protection in the field.

Effects of the 2b Protein of Cucumber mosaic virus Subgroup IB Strain IA on Different Transgene-Induced RNA Silencing Pathways

2017 ◽  
Vol 35 (2) ◽  
pp. 265-272 ◽  
Author(s):  
Mayuko Koizumi ◽  
Yumi Shimotori ◽  
Yuta Saeki ◽  
Sayaka Hirai ◽  
Shin-ichiro Oka ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
2B Protein ◽  
Silencing Pathways

scholarly journals A cucumber mosaic virus mutant lacking the 2b counter-defence protein gene provides protection against wild-type strains

2007 ◽  
Vol 88 (10) ◽  
pp. 2862-2871 ◽  
Author(s):  
Heiko Ziebell ◽  
Tina Payne ◽  
James O. Berry ◽  
John A. Walsh ◽  
John P. Carr
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
Cross Protection ◽  
Host Cells ◽  
Silencing Suppressor ◽  
Wild Type ◽  
Rna Sequences ◽  
Challenge Inoculation ◽  
Virus Mutant

Several plant virus mutants, in which genes encoding silencing suppressor proteins have been deleted, are known to induce systemic or localized RNA silencing against themselves and other RNA molecules containing homologous sequences. Thus, it is thought that many cases of cross-protection, in which infection with a mild or asymptomatic virus mutant protects plants against challenge infection with closely related virulent viruses, can be explained by RNA silencing. We found that a cucumber mosaic virus (CMV) mutant of the subgroup IA strain Fny (Fny-CMVΔ2b), which cannot express the 2b silencing suppressor protein, cross-protects tobacco (Nicotiana tabacum) and Nicotiana benthamiana plants against disease induction by wild-type Fny-CMV. However, protection is most effective only if inoculation with Fny-CMVΔ2b and challenge inoculation with wild-type CMV occurs on the same leaf. Unexpectedly, Fny-CMVΔ2b also protected plants against infection with TC-CMV, a subgroup II strain that is not closely related to Fny-CMV. Additionally, in situ hybridization revealed that Fny-CMVΔ2b and Fny-CMV can co-exist in the same tissues but these tissues contain zones of Fny-CMVΔ2b-infected host cells from which Fny-CMV appears to be excluded. Taken together, it appears unlikely that cross-protection by Fny-CMVΔ2b occurs by induction of systemic RNA silencing against itself and homologous RNA sequences in wild-type CMV. It is more likely that protection occurs through either induction of very highly localized RNA silencing, or by competition between strains for host cells or resources.

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