scholarly journals Purification of Potato Virus X and Preparation of Infectious Ribonucleic Acid by Degradation With Lithium Chloride

1968 ◽  
Vol 21 (6) ◽  
pp. 1311 ◽  
Author(s):  
RIB Francki ◽  
GD Mclean
Keyword(s):  
Lithium Chloride ◽  
Potato Virus ◽  
Ribonucleic Acid ◽  
Potato Virus X ◽  
Plant Viruses ◽  
Salt Solutions

Potato virus X (PVX) was one of the first plant viruses to be partially purified (Bawden and Pirie 1938). Purification by precipitation with salt solutions, however, resulted in aggregation of the particles. which became entwined to form extensive rope and netlike structures (Kleczkowski and Nixon 1950). Markham (1959) suggested that the problem of aggregation and the formation of gels when the virus is treated with salt solutions has prevented PYX from being extensively studied

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 Inhibition of RNA silencing by the coat protein of Pelargonium flower break virus: distinctions from closely related suppressors

2009 ◽  
Vol 90 (2) ◽  
pp. 519-525 ◽  
Author(s):  
Sandra Martínez-Turiño ◽  
Carmen Hernández
Keyword(s):  
Coat Protein ◽  
Potato Virus ◽  
Rna Silencing ◽  
Potato Virus X ◽  
Plant Viruses ◽  
Small Interfering Rnas ◽  
Silencing Suppression ◽  
Viral Suppressors

Viral-derived double-stranded RNAs (dsRNAs) activate RNA silencing, generating small interfering RNAs (siRNAs) which are incorporated into an RNA-induced silencing complex (RISC) that promotes homology-dependent degradation of cognate RNAs. To counteract this, plant viruses express RNA silencing suppressors. Here, we show that the coat protein (CP) of Pelargonium flower break virus (PFBV), a member of the genus Carmovirus, is able to efficiently inhibit RNA silencing. Interestingly, PFBV CP blocked both sense RNA- and dsRNA-triggered RNA silencing and did not preclude generation of siRNAs, which is in contrast with the abilities that have been reported for other carmoviral CPs. We have also found that PFBV CP can bind siRNAs and that this ability correlates with silencing suppression activity and enhancement of potato virus X pathogenicity. Collectively, the results indicate that PFBV CP inhibits RNA silencing by sequestering siRNAs and preventing their incorporation into a RISC, thus behaving similarly to unrelated viral suppressors but dissimilarly to orthologous ones.

scholarly journals The P25 Protein of Potato Virus X (PVX) Is the Main Pathogenicity Determinant Responsible for Systemic Necrosis in PVX-Associated Synergisms

2014 ◽  
Vol 89 (4) ◽  
pp. 2090-2103 ◽  
Author(s):  
Emmanuel Aguilar ◽  
David Almendral ◽  
Lucía Allende ◽  
Remedios Pacheco ◽  
Bong Nam Chung ◽  
...  
Keyword(s):  
Potato Virus ◽  
Rna Silencing ◽  
Potato Virus X ◽  
Threshold Level ◽  
Plant Viruses ◽  
Plum Pox Virus ◽  
Systemic Necrosis ◽  
Suppressor Activity ◽  
Content Type ◽  
Reading Frame

ABSTRACTMost plant viruses counter the RNA silencing-based antiviral defense by expressing viral suppressors of RNA silencing (VSRs). In this sense, VSRs may be regarded as virulence effectors that can be recognized by the host as avirulence (avr) factors to induceR-mediated resistance. We made use ofAgrobacterium-mediated transient coexpression of VSRs in combination withPotato virus X(PVX) to recapitulate in local tissues the systemic necrosis (SN) caused by PVX-potyvirus synergistic infections inNicotiana benthamiana. The hypersensitive response (HR)-like response was associated with an enhanced accumulation of PVX subgenomic RNAs. We further show that expression of P25, the VSR of PVX, in the presence of VSR from different viruses elicited an HR-like response inNicotianaspp. Furthermore, the expression of P25 by aPlum pox virus(PPV) vector was sufficient to induce an increase of PPV pathogenicity that led to necrotic mottling. A frameshift mutation in the P25 open reading frame (ORF) of PVX did not lead to necrosis when coexpressed with VSRs. These findings indicate that P25 is the main PVX determinant involved in eliciting a systemic HR-like response in PVX-associated synergisms. Moreover, we show that silencing ofSGT1andRAR1attenuated cell death in both PVX-potyvirus synergistic infection and the HR-like response elicited by P25. Our study underscores that P25 variants that have impaired ability to suppress RNA silencing cannot act as elicitors when synergized by the presence of other VSRs. These findings highlight the importance of RNA silencing suppression activity in the HR-like response elicited by VSRs in certain hosts.IMPORTANCEThe work presented here describes how the activity of the PVX suppressor P25 elicits an HR-like response inNicotianaspp. when overexpressed with other VSR proteins. This finding suggests that the SN response caused by PVX-associated synergisms is a delayed immune response triggered by P25, once it reaches a threshold level by the action of other VSRs. Moreover, this work supports the contention that the silencing suppressor activity of PVX P25 protein is a prerequisite for HR elicitation. We propose that unidentified avr determinants could be involved in other cases of viral synergisms in which heterologous “helper” viruses encoding strong VSRs exacerbate the accumulation of the avr-encoding virus.

scholarly journals Prevalence, distribution and control of six major potato viruses in Kenya

2020 ◽  
Author(s):  
John Onditi ◽  
Moses Nyongesa ◽  
René van der Vlugt
Keyword(s):  
Potato Virus ◽  
Leaf Roll ◽  
Potato Virus X ◽  
Plant Viruses ◽  
Multiple Infections ◽  
Potato Seed ◽  
Potato Leaf ◽  
Potato Virus S ◽  
Potato Viruses ◽  
Virus Prevalence

AbstractIn most developing countries, farmers lack sufficient supply of certified or healthy potato seed tubers. Hence, they often plant their own saved ware potato tubers, a practice that is known to contribute to spread and increase the prevalence of plant viruses. In this study, we proposed options for managing the virus based on the knowledge obtained from surveys of virus prevalence and distribution in potato cultivars grown under such conditions. Potato leaf samples randomly collected from 354 farms in five major potato-growing counties in Kenya were tested for six potato viruses; potato virus Y (PVY), potato leaf roll virus (PLRV), potato virus X (PVX), potato virus M (PVM), potato virus A (PVA) and potato virus S (PVS) through DAS-ELISA. Virus prevalence in the fields was high; 72.9% of the samples were positive for at least one of the six viruses; and 55.9% showed multiple infections. A follow-up survey conducted during three consecutive seasons, in two of the five counties, revealed that virus prevalence fluctuated across seasons. This suggested that updated information on virus prevalence might be of value for designing a virus control strategy. Distribution maps showed the presence of the viruses restricted to specific geographic regions, an indication of where control efforts should be directed. Four cultivars, Sherekea, Shangi, Kenya Karibu and Asante, grown at a high virus-prevalent area, showed low values of average ELISA absorbance (OD), suggest a field resistance to the viruses. This study demonstrated that knowledge of prevalence and distribution may be of value to identify and recommend virus resistant cultivars to replace susceptible ones, especially in the virus hotspot areas.

Assembly of flexuous plant viruses and their proteins

1976 ◽  
Vol 276 (943) ◽  
pp. 173-179 ◽  
Keyword(s):  
Potato Virus ◽  
Potato Virus Y ◽  
Potato Virus X ◽  
Plant Viruses

Recent experiments on the disassembly and assembly of some flexuous plant viruses and their proteins are described. The properties of reconstituted potato virus X and those of assembled potato virus Y protein are considered as well as the suitability of other flexuous viruses for reconstitution studies.

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 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.

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