scholarly journals Stability of recombinant plant viruses containing genes of unrelated plant viruses

2007 ◽  
Vol 88 (4) ◽  
pp. 1347-1355 ◽  
Author(s):  
Bong-Nam Chung ◽  
Tomas Canto ◽  
Peter Palukaitis
Keyword(s):  
Transgenic Plants ◽  
Transgenic Tobacco ◽  
Potato Virus ◽  
Tobacco Rattle Virus ◽  
Resistance Mechanism ◽  
Potato Virus X ◽  
Plant Viruses ◽  
Hybrid Plant ◽  
Expression Vectors ◽  
Post Inoculation

The stability of hybrid plant viruses that might arise by recombination in transgenic plants was examined using hybrid viruses derived from the viral expression vectors potato virus X (PVX) and tobacco rattle virus (TRV). The potato virus Y (PVY) NIb and HCPro open reading frames (ORFs) were introduced into PVX to generate PVX-NIb and PVX-HCPro, while the PVY NIb ORF was introduced into a vector derived from TRV RNA2 to generate TRV-NIb. All three viruses were unstable and most of the progeny viruses had lost the inserted sequences between 2 and 4 weeks post-inoculation. There was some variation in the rate of loss of part or all of the inserted sequence and the number of plants containing the deleted viruses, depending on the sequence, the host (Nicotiana tabacum vs Nicotiana benthamiana) or the vector, although none of these factors was associated consistently with the preferential loss of the inserted sequences. PVX-NIb was unable to accumulate in NIb-transgenic tobacco resistant to infection by PVY and also showed loss of the NIb insert from PVX-NIb in some NIb-transgenic tobacco plants susceptible to infection by PVY. These data indicate that such hybrid viruses, formed in resistant transgenic plants from a transgene and an unrelated virus, would be at a selective disadvantage, first by being targeted by the resistance mechanism and second by not being competitive with the parental virus.

scholarly journals Involvement of the chloroplast gene ferredoxin 1 in multiple responses of Nicotiana benthamiana to Potato virus X infection

2019 ◽  
Vol 71 (6) ◽  
pp. 2142-2156 ◽  
Author(s):  
Xue Yang ◽  
Yuwen Lu ◽  
Fang Wang ◽  
Ying Chen ◽  
Yanzhen Tian ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Mosaic Virus ◽  
Potato Virus ◽  
Tobacco Rattle Virus ◽  
Potato Virus X ◽  
Tomato Mosaic Virus ◽  
Pcr Analysis ◽  
Coat Proteins ◽  
Virus Induced Gene Silencing ◽  
Callose Deposition

Abstract The chloroplast protein ferredoxin 1 (FD1), with roles in the chloroplast electron transport chain, is known to interact with the coat proteins (CPs) of Tomato mosaic virus and Cucumber mosaic virus. However, our understanding of the roles of FD1 in virus infection remains limited. Here, we report that the Potato virus X (PVX) p25 protein interacts with FD1, whose mRNA and protein levels are reduced by PVX infection or by transient expression of p25. Silencing of FD1 by Tobacco rattle virus-based virus-induced gene silencing (VIGS) promoted the local and systemic infection of plants by PVX. Use of a drop-and-see (DANS) assay and callose staining revealed that the permeability of plasmodesmata (PDs) was increased in FD1-silenced plants together with a consistently reduced level of PD callose deposition. After FD1 silencing, quantitative reverse transcription–real-time PCR (qRT–PCR) analysis and LC-MS revealed these plants to have a low accumulation of the phytohormones abscisic acid (ABA) and salicylic acid (SA), which contributed to the decreased callose deposition at PDs. Overexpression of FD1 in transgenic plants manifested resistance to PVX infection, but the contents of ABA and SA, and the PD callose deposition were not increased in transgenic plants. Overexpression of FD1 interfered with the RNA silencing suppressor function of p25. These results demonstrate that interfering with FD1 function causes abnormal plant hormone-mediated antiviral processes and thus enhances PVX infection.

scholarly journals Peptide display on Potato virus X: molecular features of the coat protein-fused peptide affecting cell-to-cell and phloem movement of chimeric virus particles

2006 ◽  
Vol 87 (10) ◽  
pp. 3103-3112 ◽  
Author(s):  
Chiara Lico ◽  
Floriana Capuano ◽  
Giovanni Renzone ◽  
Marcello Donini ◽  
Carla Marusic ◽  
...  
Keyword(s):  
Coat Protein ◽  
Potato Virus ◽  
Potato Virus X ◽  
Structural Features ◽  
Plant Viruses ◽  
Chimeric Virus ◽  
Expression Vectors ◽  
In Planta ◽  
Virus Particles ◽  
Molecular Features

The potexvirus Potato virus X (PVX) can be modified genetically to generate chimeric virus particles (CVPs) carrying heterologous peptides fused to coat protein (CP) subunits. A spontaneous PVX mutant expressing a truncated, but functional, form of the CP has been isolated. With the aim of exploiting this virus to display peptides useful for vaccine formulations, two novel viral expression vectors based on pPVX201 (bearing the wild-type PVX genome) were constructed encoding the truncated CP. Both vectors were able to produce infectious virus particles in planta and were used to insert a panel of sequences encoding peptides of biopharmaceutical interest as N-terminal fusions to the truncated cp gene. The analysis of infection progression induced by the different constructs enabled identification of two important structural features of the fused peptide, namely tryptophan content and isoelectric point, critically affecting the formation of PVX CVPs and virus movement through the plant. These results are discussed in view of the rising interest in engineered plant viruses for development of peptide-based epitope vaccines.

scholarly journals The cysteine-rich proteins of beet necrotic yellow vein virus and tobacco rattle virus contribute to efficient suppression of silencing in roots

2012 ◽  
Vol 93 (8) ◽  
pp. 1841-1850 ◽  
Author(s):  
Ida Bagus Andika ◽  
Hideki Kondo ◽  
Masamichi Nishiguchi ◽  
Tetsuo Tamada
Keyword(s):  
Mosaic Virus ◽  
Potato Virus ◽  
Rna Silencing ◽  
Tobacco Rattle Virus ◽  
Potato Virus X ◽  
Plant Viruses ◽  
Yellow Vein ◽  
Negative Strand ◽  
Silencing Suppression ◽  
Leaves And Roots

Many plant viruses encode proteins that suppress RNA silencing, but little is known about the activity of silencing suppressors in roots. This study examined differences in the silencing suppression activity of different viruses in leaves and roots of Nicotiana benthamiana plants. Infection by tobacco mosaic virus, potato virus Y and cucumber mosaic virus but not potato virus X (PVX) resulted in strong silencing suppression activity of a transgene in both leaves and roots, whereas infection by beet necrotic yellow vein virus (BNYVV) and tobacco rattle virus (TRV) showed transgene silencing suppression in roots but not in leaves. For most viruses tested, viral negative-strand RNA accumulated at a very low level in roots, compared with considerable levels of positive-strand genomic RNA. Co-inoculation of leaves with PVX and either BNYVV or TRV produced an increase in PVX negative-strand RNA and subgenomic RNA (sgRNA) accumulation in roots. The cysteine-rich proteins (CRPs) BNYVV p14 and TRV 16K showed weak silencing suppression activity in leaves. However, when either of these CRPs was expressed from a PVX vector, there was an enhancement of PVX negative-strand RNA and sgRNA accumulation in roots compared with PVX alone. Such enhancement of PVX sgRNAs was also observed by expression of CRPs of other viruses and the well-known suppressors HC-Pro and p19 but not of the potato mop-top virus p8 CRP. These results indicate that BNYVV- and TRV-encoded CRPs suppress RNA silencing more efficiently in roots than in leaves.

scholarly journals Transgenic Tobacco Plants Expressing the Potato virus X Open Reading Frame 3 Gene Develop Specific Resistance and Necrotic Ring Symptoms After Infection with the Homologous Virus

2001 ◽  
Vol 14 (11) ◽  
pp. 1274-1285 ◽  
Author(s):  
Ken Kobayashi ◽  
Silvia Cabral ◽  
Gabriela Calamante ◽  
Sara Maldonado ◽  
Alejandro Mentaberry
Keyword(s):  
Transgenic Plants ◽  
Potato Virus ◽  
Specific Resistance ◽  
Resistance Mechanism ◽  
Potato Virus X ◽  
Open Reading Frame ◽  
Morphological Aspect ◽  
Tobacco Plants ◽  
Reading Frame ◽  
Homologous Virus

Tobacco plants were transformed with the open reading frame 3 gene from Potato virus X (PVX) coding for the p12 protein. Although the transgenic plants exhibited a normal morphological aspect, microscopic examination revealed extensive alterations in leaf tissue structure. After being challenged with PVX, the transgenic plants showed resistance to PVX infection and formation of specific leaf symptoms consisting of concentric rings encircled by necrotic borders. These novel symptoms were accompanied by biochemical changes normally associated with the hypersensitive response (HR) and were absent in noninfected transgenic plants or in PVX-infected nontransgenic plants. No equivalent virus resistance was observed after inoculation with Tobacco mosaic virus or Potato virus Y, suggesting the presence of a specific resistance mechanism. Despite development of HR-like symptoms, systemic acquired resistance was not induced in PVX-infected p12 transgenic plants. No evidence of an RNA-mediated resistance mechanism was found.

scholarly journals Transgenic Plants Expressing Potato Virus X ORF2 Protein (p24) Are Resistant to Tobacco Mosaic Virus and Ob Tobamoviruses

1998 ◽  
Vol 72 (1) ◽  
pp. 731-738 ◽  
Author(s):  
X. Ares ◽  
G. Calamante ◽  
S. Cabral ◽  
J. Lodge ◽  
P. Hemenway ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Transgenic Tobacco ◽  
Potato Virus ◽  
Potato Virus X ◽  
N Gene ◽  
Transgenic Tobacco Plants ◽  
Tobacco Plants ◽  
Virus Accumulation

ABSTRACT The p24 protein, one of the three proteins implicated in local movement of potato virus X (PVX), was expressed in transgenic tobacco plants (Nicotiana tabacum Xanthi D8 NN). Plants with the highest level of p24 accumulation exhibited a stunted and slightly chlorotic phenotype. These transgenic plants facilitate the cell-to-cell movement of a mutant of PVX that contained a frameshift mutation in p24. Upon inoculation with tobacco mosaic virus (TMV), the size of necrotic local lesions was significantly smaller in p24+ plants than in nontransgenic, control plants. Systemic resistance to tobamoviruses was also evidenced after inoculation of p24+ plants with Ob, a virus that evades the hypersensitive response provided by the N gene. In the latter case, no systemic symptoms were observed, and virus accumulation remained low or undetectable by Western immunoblot analysis and back-inoculation assays. In contrast, no differences were observed in virus accumulation after inoculation with PVX, although more severe symptoms were evident on p24-expressing plants than on control plants. Similarly, infection assays conducted with potato virus Y showed no differences between control and transgenic plants. On the other hand, a considerable delay in virus accumulation and symptom development was observed when transgenic tobacco plants containing the movement protein (MP) of TMV were inoculated with PVX. Finally, a movement defective mutant of TMV was inoculated on p24+ plants or in mixed infections with PVX on nontransgenic plants. Both types of assays failed to produce TMV infections, implying that TMV MP is not interchangeable with the PVX MPs.

Stability of Potato virus X expression vectors is related to insert size: implications for replication models and risk assessment

2007 ◽  
Vol 16 (5) ◽  
pp. 587-597 ◽  
Author(s):  
Linda Avesani ◽  
Giampiero Marconi ◽  
Francesca Morandini ◽  
Emidio Albertini ◽  
Matteo Bruschetta ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Potato Virus ◽  
Potato Virus X ◽  
Expression Vectors ◽  
Insert Size

scholarly journals Tobacco mosaic virus (TMV) and potato virus X (PVX) coat proteins confer heterologous interference to PVX and TMV infection, respectively

2006 ◽  
Vol 87 (4) ◽  
pp. 1005-1012 ◽  
Author(s):  
A. A. Bazzini ◽  
S. Asurmendi ◽  
H. E. Hopp ◽  
R. N. Beachy
Keyword(s):  
Transgenic Plants ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Potato Virus ◽  
Quaternary Structure ◽  
Systemic Infection ◽  
Potato Virus X ◽  
Coat Proteins ◽  
Local Cell ◽  
Cell Spread

Replication of Potato virus X (PVX) was reduced in transgenic protoplasts that accumulated wild-type coat protein (CPWT) of Tobacco mosaic virus (TMV) or a mutant CP, CPT42W, that produced highly ordered states of aggregation, including pseudovirions. This reaction is referred to as heterologous CP-mediated resistance. However, protoplasts expressing a CP mutant that abolished aggregation and did not produce pseudovirions, CPT28W, did not reduce PVX replication. Similarly, in transgenic tobacco plants producing TMV CPWT or CPT42W, there was a delay in local cell-to-cell spread of PVX infection that was not observed in CPT28W plants or in non-transgenic plants. The results suggest that the quaternary structure of the TMV CP regulates the mechanism(s) of heterologous CP-mediated resistance. Similarly, transgenic protoplasts that produced PVX CP conferred transient protection against infection by TMV RNA. Transgenic plants that accumulated PVX CP reduced the cell-to-cell spread of infection and resulted in a delay in systemic infection following inoculation with TMV or TMV RNA. Heterologous CP-mediated resistance was characterized by a brief delay in systemic infection, whilst homologous CP-mediated resistance conferred reduced or no systemic infection.

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