scholarly journals An aromatic amino acid and associated helix in the C-terminus of the potato leafroll virus minor capsid protein regulate systemic infection and symptom expression

2018 ◽  
Vol 14 (11) ◽  
pp. e1007451 ◽  
Author(s):  
Yi Xu ◽  
Washington Luis Da Silva ◽  
Yajuan Qian ◽  
Stewart M. Gray
Keyword(s):  
Amino Acid ◽  
Capsid Protein ◽  
Aromatic Amino Acid ◽  
Systemic Infection ◽  
Potato Leafroll Virus ◽  
Symptom Expression ◽  
Minor Capsid Protein ◽  
C Terminus ◽  
Leafroll Virus

scholarly journals The Three Essential Motifs in P0 for Suppression of RNA Silencing Activity of Potato leafroll virus Are Required for Virus Systemic Infection

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 170 ◽  
Author(s):  
Mamun-Or Rashid ◽  
Xiao-Yan Zhang ◽  
Ying Wang ◽  
Da-Wei Li ◽  
Jia-Lin Yu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Gene Silencing ◽  
Rna Silencing ◽  
Systemic Infection ◽  
Rna Degradation ◽  
Potato Leafroll Virus ◽  
Posttranscriptional Gene Silencing ◽  
Conserved Region ◽  
Leafroll Virus ◽  
The Impact

Higher plants exploit posttranscriptional gene silencing as a defense mechanism against virus infection by the RNA degradation system. Plant RNA viruses suppress posttranscriptional gene silencing using their encoded proteins. Three important motifs (F-box-like motif, G139/W140/G141-like motif, and C-terminal conserved region) in P0 of Potato leafroll virus (PLRV) were reported to be essential for suppression of RNA silencing activity. In this study, Agrobacterium-mediated transient experiments were carried out to screen the available amino acid substitutions in the F-box-like motif and G139/W140/G141-like motif that abolished the RNA silencing suppression activity of P0, without disturbing the P1 amino acid sequence. Subsequently, four P0 defective mutants derived from a full-length cDNA clone of PLRV (L76F and W87R substitutions in the F-box-like motif, G139RRR substitution in the G139/W140/G141-like motif, and F220R substitution in the C-terminal conserved region) were successfully generated by reverse PCR and used to investigate the impact of these substitutions on PLRV infectivity. The RT-PCR and western blot analysis revealed that these defective mutants affected virus accumulation in inoculated leaves and systemic movement in Nicotiana benthamiana as well as in its natural hosts, potato and black nightshade. These results further demonstrate that the RNA silencing suppressor of PLRV is required for PLRV accumulation and systemic infection.

scholarly journals Host-Dependent Requirement for the Potato leafroll virus 17-kDa Protein in Virus Movement

2002 ◽  
Vol 15 (10) ◽  
pp. 1086-1094 ◽  
Author(s):  
Lawrence Lee ◽  
Peter Palukaitis ◽  
Stewart M. Gray
Keyword(s):  
Amino Acids ◽  
Solanum Tuberosum ◽  
Nicotiana Benthamiana ◽  
Systemic Infection ◽  
Potato Leafroll Virus ◽  
Virus Movement ◽  
Wild Type ◽  
Mature Leaves ◽  
Leafroll Virus ◽  
Virus Distribution

The requirement for the 17-kDa protein (P17) of Potato leafroll virus (PLRV) in virus movement was investigated in four plant species: potato (Solanum tuberosum), Physalis floridana, Nicotiana benthamiana, and N. clevelandii. Two PLRV P17 mutants were characterized, one that does not translate the P17 and another that expresses a P17 missing the first four amino acids. The P17 mutants were able to replicate and accumulate in agroinoculated leaves of potato and P. floridana, but they were unable to move into vascular tissues and initiate a systemic infection in these plants. In contrast, the P17 mutants were able to spread systemically from inoculated leaves in both Nicotiana spp., although the efficiency of infection was reduced relative to wild-type PLRV. Examination of virus distribution in N. benthamiana plants using tissue immunoblotting techniques revealed that the wild-type PLRV and P17 mutants followed a similar movement pathway out of the inoculated leaves. Virus first moved upward to the apical tissues and then downward. The P17 mutants, however, infected fewer phloem-associated cells, were slower than wild-type PLRV in moving out of the inoculated tissue and into apical tissues, and were unable to infect any mature leaves present on the plant at the time of inoculation.

scholarly journals Mutational analysis of the proteinase function of Potato leafroll virus

2001 ◽  
Vol 82 (6) ◽  
pp. 1517-1527 ◽  
Author(s):  
Ewa Sadowy ◽  
Marek Juszczuk ◽  
Chantal David ◽  
Bruno Gronenborn ◽  
M. Danuta Hulanicka
Keyword(s):  
Capsid Protein ◽  
Potato Leafroll Virus ◽  
Catalytic Triad ◽  
Cauliflower Mosaic Virus ◽  
Expression Vectors ◽  
Viral Capsid ◽  
Potato Leaf ◽  
Viral Capsid Protein ◽  
Subgenomic Rnas ◽  
Leafroll Virus

cDNA expression vectors of Potato leafroll virus (PLRV) were used to analyse specific mutations in the proteinase and replicase domains of the proteins encoded by ORF1 and ORF2. Agrobacterium-mediated DNA transfer was used to introduce a PLRV RNA expression unit, controlled by the 35S promoter of Cauliflower mosaic virus, into potato leaf cells. Expression of unmodified PLRV cDNA led to the replication of viral genomic and subgenomic RNAs and accumulation of the viral capsid protein, whereas alteration of amino acids GDD513–515 of the replicase to VHD abolished PLRV replication. Mutations in the presumed H-D-S catalytic triad of the viral proteinase abolished the formation of viral genomic and subgenomic RNAs as well as synthesis of the viral capsid protein. Co-agroinoculation of the GDD mutant along with any of the proteinase mutants restored virus replication in leaf discs, showing that these mutants are able to complement each other. Moreover, mutation of the postulated serine residue of the catalytic triad of the proteinase altered the pattern of proteins synthesized in vitro in comparison to wild-type, further supporting the relevance of the H-D-S motif.

scholarly journals Viral Genome-Linked Protein (VPg) Controls Accumulation and Phloem-Loading of a Potyvirus in Inoculated Potato Leaves

2002 ◽  
Vol 15 (2) ◽  
pp. 138-149 ◽  
Author(s):  
Minna-Liisa Rajamäki ◽  
Jari P. T. Valkonen
Keyword(s):  
Amino Acid ◽  
Viral Genome ◽  
Systemic Infection ◽  
Phloem Loading ◽  
Cellular Level ◽  
Single Amino Acid ◽  
Solanum Commersonii ◽  
Virus Accumulation ◽  
C Terminus ◽  
Critical Boundary

The viral protein covalently linked to the 5′ end of the plus-sense, single-stranded RNA genome of potyviruses (genus Potyvirus) can be an avirulence determinant in incompatible potyvirus-host combinations in which the resistance prevents systemic virus infection. The mechanism is not well known. This study shows that virus strain-specific resistance to systemic infection with Potato virus A (PVA) in Solanum commersonii is overcome by a single amino acid (aa) substitution, His118Tyr, in the viral genome-linked protein (VPg). Virus localization and other experiments revealed that Tyr118 controls phloem loading of PVA. The critical boundary may be constituted in phloem parenchyma, companion cells, or both. Tyr118 also controls the cellular level of virus accumulation in infected leaves, including phloem cells. Amino acid substitutions at three additional positions of the central part (aa 116) and C terminus (aa 185) of the VPg and of the N terminus of the 6K2 protein (aa 5) affect virus accumulation and rate of systemic infection but are not sufficient for phloem loading of PVA. These data, together with previous studies, indicate that the PVA VPg aa residues crucial for systemic infection are host specific. Also, our data and previous studies on other potyvirus-host species combinations indicate that the central part of the VPg is a domain with universal importance to virus-host interactions required for systemic invasion of plants with potyviruses.

scholarly journals Bovine adenovirus type 3 containing heterologous protein in the C-terminus of minor capsid protein IX

Virology ◽  
2004 ◽  
Vol 320 (2) ◽  
pp. 291-300 ◽  
Author(s):  
Alexander Zakhartchouk ◽  
Wayne Connors ◽  
Andrew van Kessel ◽  
Suresh Kumar Tikoo
Keyword(s):  
Capsid Protein ◽  
Heterologous Protein ◽  
Adenovirus Type ◽  
Minor Capsid Protein ◽  
Bovine Adenovirus ◽  
C Terminus ◽  
Protein Ix ◽  
Bovine Adenovirus Type 3 ◽  
Type 3

Cloning of the gene for the capsid protein of potato leafroll virus

1989 ◽  
Vol 105 (3-4) ◽  
pp. 153-163 ◽  
Author(s):  
E. Tacke ◽  
S. Sarkar ◽  
F. Salamini ◽  
W. Rohde
Keyword(s):  
Capsid Protein ◽  
Potato Leafroll Virus ◽  
Leafroll Virus

scholarly journals The passage of Potato leafroll virus through Myzus persicae gut membrane regulates transmission efficiency

2001 ◽  
Vol 82 (1) ◽  
pp. 17-23 ◽  
Author(s):  
J. Rouzé-Jouan ◽  
L. Terradot ◽  
F. Pasquer ◽  
S. Tanguy ◽  
D. Giblot Ducray-Bourdin
Keyword(s):  
Amino Acid ◽  
Coat Protein ◽  
Myzus Persicae ◽  
Virus Transmission ◽  
Transmission Efficiency ◽  
Potato Leafroll Virus ◽  
Transmission Process ◽  
Leafroll Virus ◽  
Readthrough Protein

Potato leafroll virus (PLRV) is transmitted by aphids in a persistent manner. Although virus circulation within the aphid leading to transmission has been well characterized, the mechanisms involved in virus recognition at aphid membranes are still poorly understood. One isolate in our collection (PLRV-14.2) has been shown to be non- or only poorly transmitted by some clones of aphids belonging to the Myzus persicae complex. To determine where the transmission process was blocked within the aphid, three virus transmission procedures were used. PLRV-14.2 could not be transmitted, or was only very poorly transmitted, after acquisition from infected plants or from purified preparations. In contrast, it could be transmitted with more than 70% efficiency when microinjected. Therefore, it is concluded that the gut membrane was a barrier regulating passage of PLRV particles from the gut lumen into the haemocoel of M. persicae. Comparison of coat protein (CP) and readthrough protein (RTP) sequences between poorly and readily transmissible isolates showed that PLRV-14.2 differed from other PLRV isolates by amino acid changes in both of these proteins. It is hypothesized that at least some of the changes found in CP and/or RTP reduced virus recognition by aphid gut receptors, resulting in reduced acquisition and subsequent transmission of PLRV-14.2.

scholarly journals A Single Amino Acid Mutation in theCarnation Ringspot Virus Capsid Protein Allows Virion Formation but Prevents Systemic Infection

2001 ◽  
Vol 75 (19) ◽  
pp. 9538-9542 ◽  
Author(s):  
Tim L. Sit ◽  
Patrick R. Haikal ◽  
Anton S. Callaway ◽  
Steven A. Lommel
Keyword(s):  
Amino Acid ◽  
Capsid Protein ◽  
Protein Gene ◽  
Systemic Infection ◽  
Ringspot Virus ◽  
Single Amino Acid ◽  
Capsid Protein Gene ◽  
Virus Capsid ◽  
Virion Formation ◽  
Virus Capsid Protein

ABSTRACT A Carnation ringspot virus (CRSV) variant (1.26) was identified that accumulates virions but is incapable of forming a systemic infection. The 1.26 capsid protein gene possesses a Ser→Pro mutation at amino acid 282. Conversion of 1.26 amino acid 282 to Ser restored systemic infection, while the reciprocal mutation in wild-type CRSV abolished systemic infection. Similar mutations introduced into the related Red clover necrotic mosaic virus capsid protein gene failed to induce the packaging but nonsystemic movement phenotype. These results provide additional support for the theory that virion formation is necessary but not sufficient for systemic movement with the dianthoviruses.

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