scholarly journals RNA4-encoded p31 of beet necrotic yellow vein virus is involved in efficient vector transmission, symptom severity and silencing suppression in roots

2007 ◽  
Vol 88 (5) ◽  
pp. 1611-1619 ◽  
Author(s):  
Muhammad Danial Rahim ◽  
Ida Bagus Andika ◽  
Chenggui Han ◽  
Hideki Kondo ◽  
Tetsuo Tamada
Keyword(s):  
Sugar Beet ◽  
Rna Silencing ◽  
Viral Rna ◽  
Yellow Vein ◽  
Symptom Expression ◽  
Suppressor Activity ◽  
Vector Transmission ◽  
Efficient Vector ◽  
Silencing Suppression ◽  
Rna Accumulation

RNA3 and RNA4 of beet necrotic yellow vein virus (BNYVV) are not essential for virus multiplication, but are associated with vector-mediated infection and disease development in sugar beet roots. Here, a unique role for RNA4 in virus transmission, virulence and RNA silencing suppression was demonstrated. Mutagenic analysis revealed that the RNA4-encoded p31 open reading frame (ORF) was involved in efficient vector transmission and slight enhancement of symptom expression in some Beta species. No effects of RNA4 on virus accumulation in infected tissue were observed. Furthermore, the p31 ORF was involved in the induction of severe symptoms by BNYVV in Nicotiana benthamiana plants without affecting viral RNA accumulation. In contrast, RNA3-encoded p25, previously identified as a major contributor to symptom induction in sugar beet, had no such effect on N. benthamiana. In two different silencing suppression assays, neither p31 nor p25 was able to suppress RNA silencing in leaves, but the presence of p31 enhanced a silencing suppressor activity in roots without alteration in viral RNA accumulation. Thus, BNYVV p31 plays a multifunctional role in efficient vector transmission, enhanced symptom expression and root-specific silencing suppression.

scholarly journals Translocation of Tomato Bushy Stunt Virus P19 Protein into the Nucleus by ALY Proteins Compromises Its Silencing Suppressor Activity

2006 ◽  
Vol 80 (18) ◽  
pp. 9064-9072 ◽  
Author(s):  
Tomas Canto ◽  
Joachim F. Uhrig ◽  
Maud Swanson ◽  
Kathryn M. Wright ◽  
Stuart A. MacFarlane
Keyword(s):  
Rna Silencing ◽  
Tomato Bushy Stunt Virus ◽  
Bimolecular Fluorescence Complementation ◽  
Rna Recognition Motif ◽  
Rna Recognition ◽  
Long Distance ◽  
Suppressor Activity ◽  
Recognition Motif ◽  
Silencing Suppression ◽  
Suppressor Of Rna Silencing

ABSTRACT The P19 protein of Tomato bushy stunt virus is a potent suppressor of RNA silencing and, depending on the host species, is required for short- and long-distance virus movement and symptom production. P19 interacts with plant ALY proteins and relocalizes a subset of these proteins from the nucleus to the cytoplasm. Here we showed that coexpression by agroinfiltration in Nicotiana benthamiana of P19 and the subset of ALY proteins that are not relocalized from the nucleus interfered with the ability of P19 to suppress RNA silencing. We demonstrated that this interference correlates with the relocation of P19 from the cytoplasm into the nucleus, and by constructing and analyzing chimeric ALY genes, we showed that the C-terminal part of the central, RNA recognition motif of ALY is responsible for interaction with P19, relocalization or nonrelocalization of ALY, and inhibition of silencing suppression by P19. We studied the interaction of ALY and P19 by using the technique of bimolecular fluorescence complementation to show that these proteins associate physically in the nucleus but not detectably in the cytoplasm, and we present a model to explain the dynamics of this interaction.

scholarly journals Characterization of Pathogenicity-Associated V2 Protein of Tobacco Curly Shoot Virus

2021 ◽  
Vol 22 (2) ◽  
pp. 923
Author(s):  
Mingjun Li ◽  
Changchang Li ◽  
Kairong Jiang ◽  
Ke Li ◽  
Junlei Zhang ◽  
...  
Keyword(s):  
Rna Silencing ◽  
Viral Infections ◽  
Infectious Clone ◽  
Potato Virus X ◽  
Transient Expression Assay ◽  
Systemic Necrosis ◽  
Suppressor Activity ◽  
Amino Acid Region ◽  
Tobacco Curly Shoot Virus ◽  
Silencing Suppression

V2 proteins encoded by some whitefly-transmitted geminiviruses were reported to be functionally important proteins. However, the functions of the V2 protein of tobacco curly shoot virus (TbCSV), a monopartite begomovirus that causes leaf curl disease on tomato and tobacco in China, remains to be characterized. In our report, an Agrobacterium infiltration-mediated transient expression assay indicated that TbCSV V2 can suppress local and systemic RNA silencing and the deletion analyses demonstrated that the amino acid region 1–92 of V2, including the five predicted α-helices, are required for local RNA silencing suppression. Site-directed substitutions showed that the conserved basic and ring-structured amino acids in TbCSV V2 are critical for its suppressor activity. Potato virus X-mediated heteroexpression of TbCSV V2 in Nicotiana benthamiana induced hypersensitive response-like (HR-like) cell death and systemic necrosis in a manner independent of V2′s suppressor activity. Furthermore, TbCSV infectious clone mutant with untranslated V2 protein (TbCSV∆V2) could not induce visual symptoms, and coinfection with betasatellite (TbCSB) could obviously elevate the viral accumulation and symptom development. Interestingly, symptom recovery occurred at 15 days postinoculation (dpi) and onward in TbCSV∆V2/TbCSB-inoculated plants. The presented work contributes to understanding the RNA silencing suppression activity of TbCSV V2 and extends our knowledge of the multifunctional role of begomovirus-encoded V2 proteins during viral infections.

scholarly journals Lettuce chlorosis virus P23 Suppresses RNA Silencing and Induces Local Necrosis with Increased Severity at Raised Temperatures

2016 ◽  
Vol 106 (6) ◽  
pp. 653-662 ◽  
Author(s):  
Kenji Kubota ◽  
James C. K. Ng
Keyword(s):  
Rna Silencing ◽  
Elevated Temperatures ◽  
Fluorescent Protein ◽  
Plant Viruses ◽  
Suppressor Activity ◽  
Systemic Movement ◽  
Symptom Modulation ◽  
Green Fluorescent ◽  
Rna Accumulation ◽  
Local Necrosis

RNA silencing functions as an antivirus defense strategy in plants, one that plant viruses counter by producing viral suppressors of RNA silencing (VSRs). VSRs have been identified in three members of the genus Crinivirus but they do not all share identical suppression mechanisms. Here, we used Agrobacterium co-infiltration assays to investigate the suppressor activity of proteins encoded by Lettuce chlorosis virus (LCV). Of 7 LCV proteins (1b, P23, HSP70 homolog, P60, CP, CPm, and P27) tested for the suppression of silencing of green fluorescent protein (GFP) expression in wild-type Nicotiana benthamiana plants, only P23 suppressed the onset of local silencing. Small-interfering (si)RNA accumulation was reduced in leaves co-infiltrated with P23, suggesting that P23 inhibited the accumulation or enhanced the degradation of siRNA. P23 also inhibited the cell-to-cell and systemic movement of RNA silencing in GFP-expressing transgenic N. benthamiana plants. Expression of P23 via agroinfiltration of N. benthamiana leaves induced local necrosis that increased in severity at elevated temperatures, a novelty given that a direct temperature effect on necrosis severity has not been reported for the other crinivirus VSRs. These results further affirm the sophistication of crinivirus VSRs in mediating the evasion of host’s antiviral defenses and in symptom modulation.

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 Viral RNA Silencing Suppression: The Enigma of Bunyavirus NSs Proteins

Viruses ◽  
2016 ◽  
Vol 8 (7) ◽  
pp. 208 ◽  
Author(s):  
Marcio Hedil ◽  
Richard Kormelink
Keyword(s):  
Rna Silencing ◽  
Viral Rna ◽  
Silencing Suppression

scholarly journals Variability in the level of RNA silencing suppression caused by triple gene block protein 1 (TGBp1) from various potexviruses during infection

2009 ◽  
Vol 90 (4) ◽  
pp. 1014-1024 ◽  
Author(s):  
Hiroko Senshu ◽  
Johji Ozeki ◽  
Ken Komatsu ◽  
Masayoshi Hashimoto ◽  
Kouji Hatada ◽  
...  
Keyword(s):  
Virus Infection ◽  
Rna Silencing ◽  
Triple Gene Block ◽  
Plant Viruses ◽  
Virus Species ◽  
Suppressor Activity ◽  
Gene Block ◽  
Gfp Fluorescence ◽  
Silencing Suppression ◽  
Triple Gene Block Protein

RNA silencing is an important defence mechanism against virus infection, and many plant viruses encode RNA silencing suppressors as a counter defence. In this study, we analysed the RNA silencing suppression ability of multiple virus species of the genus Potexvirus. Nicotiana benthamiana plants exhibiting RNA silencing of a green fluorescent protein (GFP) transgene showed reversal of GFP fluorescence when systemically infected with potexviruses. However, the degree of GFP fluorescence varied among potexviruses. Agrobacterium-mediated transient expression assay in N. benthamiana leaves demonstrated that the triple gene block protein 1 (TGBp1) encoded by these potexviruses has drastically different levels of silencing suppressor activity, and these differences were directly related to variations in the silencing suppression ability during virus infection. These results suggest that suppressor activities differ even among homologous proteins encoded by viruses of the same genus, and that TGBp1 contributes to the variation in the level of RNA silencing suppression by potexviruses. Moreover, we investigated the effect of TGBp1 encoded by Plantago asiatica mosaic virus (PlAMV), which exhibited a strong suppressor activity, on the accumulation of microRNA, virus genomic RNA and virus-derived small interfering RNAs.

scholarly journals Identification of amino acids of the beet necrotic yellow vein virus p25 protein required for induction of the resistance response in leaves of Beta vulgaris plants

2008 ◽  
Vol 89 (5) ◽  
pp. 1314-1323 ◽  
Author(s):  
Soutaro Chiba ◽  
Masaki Miyanishi ◽  
Ida Bagus Andika ◽  
Hideki Kondo ◽  
Tetsuo Tamada
Keyword(s):  
Sugar Beet ◽  
Beta Vulgaris ◽  
Specific Interaction ◽  
Viral Rna ◽  
Yellow Vein ◽  
Single Amino Acid ◽  
Polymyxa Betae ◽  
Resistance Response ◽  
Resistance Phenotype ◽  
Wild Beet

The RNA3-encoded p25 protein of beet necrotic yellow vein virus (BNYVV) is responsible for the production of rhizomania symptoms of sugar beet roots (Beta vulgaris subsp. vulgaris). Here, it was found that the presence of the p25 protein is also associated with the resistance response in rub-inoculated leaves of sugar beet and wild beet (Beta vulgaris subsp. maritima) plants. The resistance phenotype displayed a range of symptoms from no visible lesions to necrotic or greyish lesions at the inoculation site, and only very low levels of virus and viral RNA accumulated. The susceptible phenotype showed large, bright yellow lesions and developed high levels of virus accumulation. In roots after Polymyxa betae vector inoculation, however, no drastic differences in virus and viral RNA accumulation levels were found between plants with susceptible and resistant phenotypes, except at an early stage of infection. There was a genotype-specific interaction between BNYVV strains and two selected wild beet lines (MR1 and MR2) and sugar beet cultivars. Sequence analysis of natural BNYVV isolates and site-directed mutagenesis of the p25 protein revealed that 3 aa residues at positions 68, 70 and 179 are important in determining the resistance phenotype, and that host-genotype specificity is controlled by single amino acid changes at position 68. The mechanism of the occurrence of resistance-breaking BNYVV strains is discussed.

scholarly journals Olive mild mosaic virus coat protein and p6 are suppressors of RNA silencing and their silencing confers resistance against OMMV

2018 ◽  
Author(s):  
CMR Varanda ◽  
P Materatski ◽  
MD Campos ◽  
MIE Clara ◽  
G Nolasco ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Rna Silencing ◽  
Plant Viruses ◽  
Mild Mosaic ◽  
Suppressor Activity ◽  
Complementary Action ◽  
Mild Mosaic Virus ◽  
Silencing Suppression ◽  
Viral Suppressors ◽  
Viral Accumulation

AbstractRNA silencing is an important defense mechanism in plants, yet several plant viruses encode proteins that suppress it. Here the genome of Olive mild mosaic virus (OMMV) was screened for silencing suppressors using a green fluorescent based transient suppression assay. The full OMMV cDNA and 5 different OMMV open reading frames (ORFs) were cloned into Gateway binary destination vector pK7WG2, transformed into Agrobacterium tumefaciens C58C1 and agroinfiltrated into Nicotiana benthamiana 16C plants. Among all ORFs tested, CP and p6 showed suppressor activity, with CP showing a significant higher activity when compared to p6, yet lower than that of the full OMMV. This suggests that OMMV silencing suppression results from a complementary action of both CP and p6.Such discovery led to the use of those viral suppressors in the development of OMMV resistant plants through pathogen-derived resistance (PDR) based on RNA silencing. Two hairpin constructs targeting each suppressor were agroinfiltrated in N. benthamiana plants which were then inoculated with OMMV RNA. When silencing of both suppressors was achieved, a highly significant reduction in viral accumulation and symptom attenuation was observed as compared to that seen when each construct was used alone, and to the respective controls, thus showing clear effectiveness against OMMV infection. Data here obtained indicate that the use of both OMMV viral suppressors as transgenes is a very efficient and promising approach to obtain plants resistant to OMMV.ImportanceOMMV silencing suppressors were determined. Among all ORFs tested, CP and p6 showed suppressor activity, with CP showing a significant higher activity when compared to p6, yet lower than that of the full OMMV, suggesting a complementary action of both CP and p6 in silencing suppression.This is the first time that a silencing suppressor was found in a necrovirus and that two independent proteins act as silencing suppressors in a member of the Tombusviridae family.When silencing of both suppressors was achieved, a highly significant reduction in viral accumulation and symptom attenuation was observed as compared to that seen when each was used alone, thus showing clear effectiveness against OMMV infection. A high percentage of resistant plants was obtained (60%), indicating that the use of both OMMV viral suppressors as transgenes is a very efficient and promising approach to obtain plants resistant to OMMV.

A sensitive and rapid RNA silencing suppressor activity assay based on alfalfa mosaic virus expression vector

2019 ◽  
Vol 272 ◽  
pp. 197733 ◽  
Author(s):  
Mireya Martínez-Pérez ◽  
José A. Navarro ◽  
Vicente Pallás ◽  
Jesús A. Sánchez-Navarro
Keyword(s):  
Mosaic Virus ◽  
Rna Silencing ◽  
Expression Vector ◽  
Alfalfa Mosaic Virus ◽  
Silencing Suppressor ◽  
Activity Assay ◽  
Suppressor Activity ◽  
Rna Silencing Suppressor ◽  
Virus Expression
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