scholarly journals A Viral Protein Suppresses siRNA-directed Interference in Tobacco Mosaic Virus Infection

2005 ◽  
Vol 37 (4) ◽  
pp. 248-253 ◽  
Author(s):  
Ming-Min Zhao ◽  
De-Rong An ◽  
Guang-Hua Huang ◽  
Zu-Hua He ◽  
Jiang-Ye Chen
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Plant Viruses ◽  
Negative Control ◽  
Transcriptional Gene Silencing ◽  
Potato Virus A ◽  
Post Transcriptional Gene Silencing ◽  
Tobacco Mosaic Virus Infection ◽  
Helper Component Proteinase ◽  
Rna Accumulation

Abstract Plant viruses encode suppressors of post-transcriptional gene silencing (PTGS), an adaptive defense response that limits virus replication and its spread in plants. The helper component proteinase (HC-Pro) of the potato virus A (PVA, genus Potyvirus) suppresses PTGS of silenced transgenes. Here, the effect of HC-Pro on siRNA-directed interference in the tobacco mosaic virus (TMV) was examined by using a transient Agrobacterium tumefaciens-based delivery system in intact tissues. It was shown that the interference effect was completely blocked by co-infiltration with HC-Pro plus siRNA constructs in both systemic and hypersensitive hosts. In the system host, all plants agro-infiltrated with HC-Pro plus siRNA constructs displayed the same symptoms as the negative control. Meanwhile, TMV RNA accumulation was found to be abundant in the upper leaves using reverse transcriptase-PCR (RT-PCR) and Northern blot assays. On the contrary, plants agro-infiltrated with the siRNA construct alone were free of symptoms. Therefore, our study suggests that the transient expression of HC-Pro inhibited the siRNA-directed host defenses against TMV infection.

scholarly journals Differential Virulence by Strains of Cucumber mosaic virus is Mediated by the 2b Gene

2002 ◽  
Vol 15 (9) ◽  
pp. 947-955 ◽  
Author(s):  
Bu-Jun Shi ◽  
Peter Palukaitis ◽  
Robert H. Symons
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Kinetic Studies ◽  
Transcriptional Gene Silencing ◽  
Long Distance ◽  
Post Transcriptional Gene Silencing ◽  
Subgroup Ii ◽  
2B Protein ◽  
Rna Accumulation ◽  
Long Distance Movement

The approximately 12-kDa 2b protein, encoded by all cucumoviruses, had been shown to play an important role in viral long-distance movement, hypervirulence, and suppression of post-transcriptional gene silencing. The role of the 2b gene in the hypervirulence of Cucumber mosaic virus (CMV) and whether hypervirulence was linked to movement were analyzed using a hybrid virus (CMV-qw), generated by replacing the 2b gene in a subgroup II strain, Q-CMV, with the 2b gene from a subgroup IA strain, WAII-CMV. CMV-qw was more virulent than Q-CMV or WAII-CMV on most of the host plant species tested. Northern blot and nucleotide sequence analyses demonstrated that CMV-qw was stably maintained during the course of infection and upon passage. Kinetic studies revealed that the hypervirulence induced by the hybrid virus was associated with neither increased viral RNA accumulation nor more rapid viral movement per se, suggesting that other functions of the 2b protein are important in determining the hypervirulence.

scholarly journals Identification of Novel Inhibitors for Tobacco Mosaic Virus Infection in Solanaceae Plants

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Archana Prabahar ◽  
Subashini Swaminathan ◽  
Arul Loganathan ◽  
Ramalingam Jegadeesan
Keyword(s):  
Virtual Screening ◽  
Rna Polymerase ◽  
Tobacco Mosaic Virus ◽  
Small Molecules ◽  
Mosaic Virus ◽  
Catalytic Domain ◽  
Docking Analysis ◽  
Catalytic Sites ◽  
Capping Enzyme ◽  
Tobacco Mosaic Virus Infection

Tobacco mosaic virus (TMV) infects several crops of economic importance (e.g., tomato) and remains as one of the major concerns to the farmers. TMV enters the host cell and produces the capping enzyme RNA polymerase. The viral genome replicates further to produce multiple mRNAs which encodes several proteins, including the coat protein and an RNA-dependent RNA polymerase (RdRp), as well as the movement protein. TMV replicase domain was chosen for the virtual screening studies against small molecules derived from ligand databases such as PubChem and ChemBank. Catalytic sites of the RdRp domain were identified and subjected to docking analysis with screened ligands derived from virtual screening LigandFit. Small molecules that interact with the target molecule at the catalytic domain region amino acids, GDD, were chosen as the best inhibitors for controlling the TMV replicase activity.

scholarly journals Cucumber mosaic virus Infection Transiently Breaks dsRNA-Induced Transgenic Immunity to Potato virus Y in Tobacco

2003 ◽  
Vol 16 (10) ◽  
pp. 936-944 ◽  
Author(s):  
Neena Mitter ◽  
Emy Sulistyowati ◽  
Ralf G. Dietzgen
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Potato Virus ◽  
Potato Virus Y ◽  
Defense Mechanism ◽  
Transcriptional Gene Silencing ◽  
Mrna Levels ◽  
Post Transcriptional Gene Silencing ◽  
The Stability ◽  
High Level

Post-transcriptional gene silencing (PTGS), an intrinsic plant defense mechanism, can be efficiently triggered by double stranded (ds)RNA-producing transgenes and can provide high level virus resistance by specific targeting of cognate viral RNA. The discovery of virus-encoded suppressors of PTGS led to concerns about the stability of such resistance. Here, we show that Cucumber mosaic virus (CMV) is able to suppress dsRNA-induced PTGS and the associated Potato virus Y (PVY) immunity in tobacco. CMV suppression supported only a transient PVY accumulation and did not prevent recovery of the transgenic plants from PVY infection. CMV inoculation resulted in strongly increased transgene mRNA levels due to suppression of PTGS, but accumulation of PVY-specific small interfering (si)RNA was unaffected. However, PVY accumulation in previously immune plants resulted in increased PVY siRNA levels and transgene mRNA was no longer detected, despite the presence of CMV. Transgene mRNA returned to high levels once PVY was no longer detected in CMV-infected plants. Recovered and chronically CMV-infected tissues were immune to further PVY infection.

scholarly journals Actin Cytoskeleton Is Involved in Targeting of a Viral Hsp70 Homolog to the Cell Periphery

2005 ◽  
Vol 79 (22) ◽  
pp. 14421-14428 ◽  
Author(s):  
Alexey I. Prokhnevsky ◽  
Valera V. Peremyslov ◽  
Valerian V. Dolja
Keyword(s):  
Actin Cytoskeleton ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Fluorescent Proteins ◽  
Cell Movement ◽  
Plant Viruses ◽  
Cell Periphery ◽  
Virus Particles ◽  
Shock Proteins

ABSTRACT The cell-to-cell movement of plant viruses involves translocation of virus particles or nucleoproteins to and through the plasmodesmata (PDs). As we have shown previously, the movement of the Beet yellows virus requires the concerted action of five viral proteins including a homolog of cellular ∼70-kDa heat shock proteins (Hsp70h). Hsp70h is an integral component of the virus particles and is also found in PDs of the infected cells. Here we investigate subcellular distribution of Hsp70h using transient expression of Hsp70h fused to three spectrally distinct fluorescent proteins. We found that fluorophore-tagged Hsp70h forms motile granules that are associated with actin microfilaments, but not with microtubules. In addition, immobile granules were observed at the cell periphery. A pairwise appearance of these granules at the opposite sides of cell walls and their colocalization with the movement protein of Tobacco mosaic virus indicated an association of Hsp70h with PDs. Treatment with various cytoskeleton-specific drugs revealed that the intact actomyosin motility system is required for trafficking of Hsp70h in cytosol and its targeting to PDs. In contrast, none of the drugs interfered with the PD localization of Tobacco mosaic virus movement protein. Collectively, these findings suggest that Hsp70h is translocated and anchored to PDs in association with the actin cytoskeleton.

scholarly journals Effect of Yeast CTA1 Gene Expression on Response of Tobacco Plants to Tobacco Mosaic Virus Infection

2002 ◽  
Vol 129 (3) ◽  
pp. 1032-1044 ◽  
Author(s):  
Andrzej Talarczyk ◽  
Magdalena Krzymowska ◽  
Wojciech Borucki ◽  
Jacek Hennig
Keyword(s):  
Gene Expression ◽  
Virus Infection ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Tobacco Plants ◽  
Tobacco Mosaic Virus Infection ◽  
Mosaic Virus Infection
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