scholarly journals Suppressors of RNA Silencing Encoded by the Components of the Cotton Leaf Curl Begomovirus-BetaSatellite Complex

2011 ◽  
Vol 24 (8) ◽  
pp. 973-983 ◽  
Author(s):  
Imran Amin ◽  
Khadim Hussain ◽  
Rashid Akbergenov ◽  
Jitender S. Yadav ◽  
Javaria Qazi ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Rna Silencing ◽  
Cotton Leaf ◽  
Small Interfering Rnas ◽  
In Planta ◽  
Suppressor Activity ◽  
Natural Defense ◽  
Or Gene ◽  
First Time ◽  
Leaf Curl

Begomoviruses (family Geminiviridae) are single-stranded DNA viruses transmitted by the whitefly Bemisia tabaci. Many economically important diseases in crops are caused by begomoviruses, particularly in tropical and subtropical environments. These include the betasatellite-associated begomoviruses causing cotton leaf curl disease (CLCuD) that causes significant losses to a mainstay of the economy of Pakistan, cotton. RNA interference (RNAi) or gene silencing is a natural defense response of plants against invading viruses. In counter-defense, viruses encode suppressors of gene silencing that allow them to effectively invade plants. Here, we have analyzed the ability of the begomovirus Cotton leaf curl Multan virus (CLCuMV) and its associated betasatellite, Cotton leaf curl Multan β-satellite (CLCuMB) which, together, cause CLCuD, and the nonessential alphasatellite (Cotton leaf curl Multan alphasatellite [CLCuMA]) for their ability to suppress gene silencing in Nicotiana benthamiana. The results showed that CLCuMV by itself was unable to efficiently block silencing. However, in the presence of the betasatellite, gene silencing was entirely suppressed. Silencing was not affected in any way when infections included CLCuMA, although the alphasatellite was, for the first time, shown to be a target of RNA silencing, inducing the production in planta of specific small interfering RNAs, the effectors of silencing. Subsequently, using a quantitative real-time polymerase chain reaction assay and Northern blot analysis, the ability of all proteins encoded by CLCuMV and CLCuMB were assessed for their ability to suppress RNAi and the relative strengths of their suppression activity were compared. The analysis showed that the V2, C2, C4, and βC1 proteins exhibited suppressor activity, with the V2 showing the strongest activity. In addition, V2, C4, and βC1 were examined for their ability to bind RNA and shown to have distinct specificities. Although each of these proteins has, for other begomoviruses or betasatellites, been previously shown to have suppressor activity, this is the first time all proteins encoded by a geminiviruses (or begomovirus-betasatellite complex) have been examined and also the first for which four separate suppressors have been identified.

scholarly journals RNA Silencing against Geminivirus: Complementary Action of Posttranscriptional Gene Silencing and Transcriptional Gene Silencing in Host Recovery

2008 ◽  
Vol 83 (3) ◽  
pp. 1332-1340 ◽  
Author(s):  
Edgar A. Rodríguez-Negrete ◽  
Jimena Carrillo-Tripp ◽  
Rafael F. Rivera-Bustamante
Keyword(s):  
Gene Silencing ◽  
Intergenic Region ◽  
Rna Silencing ◽  
Methylation Status ◽  
Inverse Correlation ◽  
Plant Viruses ◽  
Transcriptional Gene Silencing ◽  
Small Interfering Rnas ◽  
Coding Region ◽  
Natural Defense

ABSTRACT RNA silencing in plants is a natural defense system mechanism against invading nucleic acids such as viruses. Geminiviruses, a family of plant viruses characterized by a circular, single-stranded DNA genome, are thought to be both inducers and targets of RNA silencing. Some natural geminivirus-host interactions lead to symptom remission or host recovery, a process commonly associated with RNA silencing-mediated defense. Pepper golden mosaic virus (PepGMV)-infected pepper plants show a recovery phenotype, which has been associated with the presence of virus-derived small RNAs. The results presented here suggest that PepGMV is targeted by both posttranscriptional and transcriptional gene silencing mechanisms. Two types of virus-related small interfering RNAs (siRNAs) were detected: siRNAs of 21 to 22 nucleotides (nt) in size that are related to the coding regions (Rep, TrAP, REn, and movement protein genes) and a 24-nt population primarily associated to the intergenic regions. Methylation levels of the PepGMV A intergenic and coat protein (CP) coding region were measured by a bisulfite sequencing approach. An inverse correlation was observed between the methylation status of the intergenic region and the concentration of viral DNA and symptom severity. The intergenic region also showed a methylation profile conserved in all times analyzed. The CP region, on the other hand, did not show a defined profile, and its methylation density was significantly lower than the one found on the intergenic region. The participation of both PTGS and TGS mechanisms in host recovery is discussed.

scholarly journals Maintenance of an Old World Betasatellite by a New World Helper Begomovirus and Possible Rapid Adaptation of the Betasatellite

2009 ◽  
Vol 83 (18) ◽  
pp. 9347-9355 ◽  
Author(s):  
Muhammad Shah Nawaz-ul-Rehman ◽  
Shahid Mansoor ◽  
Rob W. Briddon ◽  
Claude M. Fauquet
Keyword(s):  
New World ◽  
Cotton Leaf ◽  
Old World ◽  
Tropical Regions ◽  
Cabbage Leaf Curl Virus ◽  
Chili Leaf Curl Betasatellite ◽  
Serious Disease ◽  
Leaf Curl Virus ◽  
First Time ◽  
Leaf Curl

ABSTRACT Begomoviruses (family Geminiviridae) cause major losses to crops throughout the tropical regions of the world. Begomoviruses originating from the New World (NW) and the Old World (OW) are genetically distinct. Whereas the majority of OW begomoviruses have monopartite genomes and whereas most of these associate with a class of symptom-modulating satellites (known as betasatellites), the genomes of NW begomoviruses are exclusively bipartite and do not associate with satellites. Here, we show for the first time that a betasatellite (cotton leaf curl Multan betasatellite [CLCuMuB]) associated with a serious disease of cotton across southern Asia is capable of interacting with a NW begomovirus. In the presence of CLCuMuB, the symptoms of the NW cabbage leaf curl virus (CbLCuV) are enhanced in Nicotiana benthamiana. However, CbLCuV was unable to interact with a second betasatellite, chili leaf curl betasatellite. Although CbLCuV can transreplicate CLCuMuB, satellite accumulation levels in plants were low. However, progeny CLCuMuB isolated after just one round of infection with CbLCuV contained numerous mutations. Reinoculation of one such progeny CLCuMuB with CbLCuV to N. benthamiana yielded infections with significantly higher satellite DNA levels. This suggests that betasatellites can rapidly adapt for efficient transreplication by a new helper begomovirus, including begomoviruses originating from the NW. Although the precise mechanism of transreplication of betasatellites by begomoviruses remains unknown, an analysis of betasatellite mutants suggests that the sequence(s) required for maintenance of CLCuMuB by one of its cognate begomoviruses (cotton leaf curl Rajasthan virus) differs from the sequences required for maintenance by CbLCuV. The significance of these findings and, particularly, the threat that betasatellites pose to agriculture in the NW, are discussed.

scholarly journals Cotton Leaf Curl Multan virus C4 protein suppresses both transcriptional and post-transcriptional gene silencing by interacting with SAM synthetase

2018 ◽  
Vol 14 (8) ◽  
pp. e1007282 ◽  
Author(s):  
Asigul Ismayil ◽  
Yakupjan Haxim ◽  
Yunjing Wang ◽  
Huangai Li ◽  
Lichao Qian ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Transcriptional Gene Silencing ◽  
Cotton Leaf ◽  
Post Transcriptional Gene Silencing ◽  
Sam Synthetase ◽  
Leaf Curl

scholarly journals Mimic Phosphorylation of a βC1 Protein Encoded by TYLCCNB Impairs Its Functions as a Viral Suppressor of RNA Silencing and a Symptom Determinant

2017 ◽  
Vol 91 (16) ◽  
Author(s):  
Xueting Zhong ◽  
Zhan Qi Wang ◽  
Ruyuan Xiao ◽  
Linge Cao ◽  
Yaqin Wang ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Rna Silencing ◽  
Mechanistic Explanation ◽  
Inhibitory Effect ◽  
Transcriptional Gene Silencing ◽  
Yellow Leaf ◽  
Viral Suppressor ◽  
Content Type ◽  
Suppressor Of Rna Silencing ◽  
Leaf Curl

ABSTRACT Phosphorylation of the βC1 protein encoded by the betasatellite of tomato yellow leaf curl China virus (TYLCCNB-βC1) by SNF1-related protein kinase 1 (SnRK1) plays a critical role in defense of host plants against geminivirus infection in Nicotiana benthamiana. However, how phosphorylation of TYLCCNB-βC1 impacts its pathogenic functions during viral infection remains elusive. In this study, we identified two additional tyrosine residues in TYLCCNB-βC1 that are phosphorylated by SnRK1. The effects of TYLCCNB-βC1 phosphorylation on its functions as a viral suppressor of RNA silencing (VSR) and a symptom determinant were investigated via phosphorylation mimic mutants in N. benthamiana plants. Mutations that mimic phosphorylation of TYLCCNB-βC1 at tyrosine 5 and tyrosine 110 attenuated disease symptoms during viral infection. The phosphorylation mimics weakened the ability of TYLCCNB-βC1 to reverse transcriptional gene silencing and to suppress posttranscriptional gene silencing and abolished its interaction with N. benthamiana ASYMMETRIC LEAVES 1 in N. benthamiana leaves. The mimic phosphorylation of TYLCCNB-βC1 had no impact on its protein stability, subcellular localization, or self-association. Our data establish an inhibitory effect of phosphorylation of TYLCCNB-βC1 on its pathogenic functions as a VSR and a symptom determinant and provide a mechanistic explanation of how SnRK1 functions as a host defense factor. IMPORTANCE Tomato yellow leaf curl China virus (TYLCCNV), which causes a severe yellow leaf curl disease in China, is a monopartite geminivirus associated with the betasatellite (TYLCCNB). TYLCCNB encodes a single pathogenicity protein, βC1 (TYLCCNB-βC1), which functions as both a viral suppressor of RNA silencing (VSR) and a symptom determinant. Here, we show that mimicking phosphorylation of TYLCCNB-βC1 weakens its ability to reverse transcriptional gene silencing, to suppress posttranscriptional gene silencing, and to interact with N. benthamiana ASYMMETRIC LEAVES 1. To our knowledge, this is the first report establishing an inhibitory effect of phosphorylation of TYLCCNB-βC1 on its pathogenic functions as both a VSR and a symptom determinant and to provide a mechanistic explanation of how SNF1-related protein kinase 1 acts as a host defense factor. These findings expand the scope of phosphorylation-mediated defense mechanisms and contribute to further understanding of plant defense mechanisms against geminiviruses.

scholarly journals Functional Analysis of Gene-Silencing Suppressors from Tomato Yellow Leaf Curl Disease Viruses

2012 ◽  
Vol 25 (10) ◽  
pp. 1294-1306 ◽  
Author(s):  
Ana P. Luna ◽  
Gabriel Morilla ◽  
Olivier Voinnet ◽  
Eduardo R. Bejarano
Keyword(s):  
Gene Silencing ◽  
Viral Proteins ◽  
Tomato Yellow Leaf ◽  
Yellow Leaf ◽  
Silencing Suppression ◽  
Viral Suppressors ◽  
Leaf Curl Virus ◽  
First Time ◽  
Leaf Curl Disease ◽  
Leaf Curl

Tomato yellow leaf curl disease (TYLCD) is caused by a complex of phylogenetically related Begomovirus spp. that produce similar symptoms when they infect tomato plants but have different host ranges. In this work, we have evaluated the gene-silencing-suppression activity of C2, C4, and V2 viral proteins isolated from the four main TYLCD-causing strains in Spain in Nicotiana benthamiana. We observed varying degrees of local silencing suppression for each viral protein tested, with V2 proteins from all four viruses exhibiting the strongest suppression activity. None of the suppressors were able to avoid the spread of the systemic silencing, although most produced a delay. In order to test the silencing-suppression activity of Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Sardinia virus (TYLCSV) proteins in a shared (tomato) and nonshared (bean) host, we established novel patch assays. Using these tools, we found that viral proteins from TYLCV were able to suppress silencing in both hosts, whereas TYLCSV proteins were only effective in tomato. This is the first time that viral suppressors from a complex of disease-causing geminiviruses have been subject to a comprehensive analysis using two economically important crop hosts, as well as the established N. benthamiana plant model.

scholarly journals Molecular Characterization and Transmission Study of the Begomovirus on Hollyhock Plant Causing Leaf Curl Disease for the First Time in Province Punjab, Pakistan

2022 ◽  
Author(s):  
Hajra Azeem ◽  
Rashida Perveen ◽  
Muhammad Nouman Tahir ◽  
Ummad-ud-din Umar ◽  
Fatih Ölmez ◽  
...  
Keyword(s):  
Ornamental Plant ◽  
Cotton Leaf ◽  
Leaf Curling ◽  
Medicinal Value ◽  
Transmission Study ◽  
Alcea Rosea ◽  
First Time ◽  
Leaf Curl Disease ◽  
Positive Results ◽  
Leaf Curl

Abstract I. Background: Hollyhock (Alcea rosea) is an ornamental plant belonging to the Malvaceae family and has a remarkable aesthetic and medicinal value. Previously in Pakistan, the hollyhock plant was not found to be infected by begomovirus and the plant first time showed the symptoms of typical leaf curling, puckering as well as thickened veins. II. Methods and Results: During the year 2018, symptomatic samples of the hollyhock plants were collected that exhibited characteristic typical leaf curling, puckering as well as thickened veins. DNA was extracted from the samples and the PCR technique was optimized for the detection of begomovirus followed by sequencing. The samples were detected to be infected with begomovirus by using Av/Ac core, Begomo 01/02, and CLCV 01/02 primer showed positive results with 579bp, 2.8kb, and 1.1kb nucleotide respectively. The betasatellite was amplified by using beta01/02 and CLCuMuBF11/R33 showed positive results with 1400bp and 481bp respectively. Sequencing results showed that diseased hollyhock plants were associated with Cotton leaf curl Multan virus-Rajasthan strain along with Cotton leaf curl Multan betasatellite. III. Conclusion: Hollyhock plants infected by begomovirus has been reported for the first time as a possible source of virus inoculum from Pakistan.

scholarly journals Tomato yellow leaf curl Sardinia virus can overcome transgene-mediated RNA silencing of two essential viral genes

2004 ◽  
Vol 85 (6) ◽  
pp. 1745-1749 ◽  
Author(s):  
Emanuela Noris ◽  
Alessandra Lucioli ◽  
Raffaela Tavazza ◽  
Piero Caciagli ◽  
Gian Paolo Accotto ◽  
...  
Keyword(s):  
Rna Silencing ◽  
Threshold Level ◽  
Tomato Yellow Leaf ◽  
Transgene Silencing ◽  
Yellow Leaf ◽  
Small Interfering Rnas ◽  
Viral Genes ◽  
Infected Cells ◽  
Virus Spreading ◽  
Leaf Curl

To evaluate RNA silencing for the control of geminivirus infection, two classes of post-transcriptionally silenced (PTS) plants were tested using Tomato yellow leaf curl Sardinia virus (TYLCSV) Rep-210-transgenic plants, a sense×antisense hybrid and two multicopy sense lines. In both classes, PTS plants accumulated low or undetectable amounts of Rep-210 protein and mRNA but high amounts of Rep-210 small interfering RNAs. PTS plants were susceptible to TYLCSV when challenged by agroinoculation or using high viruliferous whitefly (Bemisia tabaci) pressure, although some plants were resistant at low whitefly pressure. Delayed infections were also observed, indicating that TYLCSV could overcome transgene silencing of rep and of the nested C4 gene. TYLCSV infection boosted transgene silencing but this did not lead to recovery. The data suggest that if the virus reaches a threshold level of expression/replication in the initially infected cells then virus spreading can no longer be prevented.

scholarly journals Identification and Functional Analysis of Four RNA Silencing Suppressors in Begomovirus Croton Yellow Vein Mosaic Virus

2022 ◽  
Vol 12 ◽  
Author(s):  
Ying Zhai ◽  
Anirban Roy ◽  
Hao Peng ◽  
Daniel L. Mullendore ◽  
Gurpreet Kaur ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Rna Silencing ◽  
Cell Movement ◽  
Yellow Vein ◽  
Silencing Suppressor ◽  
Monopartite Begomovirus ◽  
Yellow Vein Mosaic Virus ◽  
First Time ◽  
Leaf Curl Disease ◽  
Leaf Curl

Croton yellow vein mosaic virus (CYVMV), a species in the genus Begomovirus, is a prolific monopartite begomovirus in the Indian sub-continent. CYVMV infects multiple crop plants to cause leaf curl disease. Plants have developed host RNA silencing mechanisms to defend the threat of viruses, including CYVMV. We characterized four RNA silencing suppressors, namely, V2, C2, and C4 encoded by CYVMV and betasatellite-encoded C1 protein (βC1) encoded by the cognate betasatellite, croton yellow vein betasatellite (CroYVMB). Their silencing suppressor functions were verified by the ability of restoring the β-glucuronidase (GUS) activity suppressed by RNA silencing. We showed here for the first time that V2 was capable of self-interacting, as well as interacting with the V1 protein, and could be translocalized to the plasmodesmata in the presence of CYVMV. The knockout of either V2 or V1 impaired the intercellular mobility of CYVMV, indicating their novel coordinated roles in the cell-to-cell movement of the virus. As pathogenicity determinants, each of V2, C2, and C4 could induce typical leaf curl symptoms in Nicotiana benthamiana plants even under transient expression. Interestingly, the transcripts and proteins of all four suppressors could be detected in the systemically infected leaves with no correlation to symptom induction. Overall, our work identifies four silencing suppressors encoded by CYVMV and its cognate betasatellite and reveals their subcellular localizations, interaction behavior, and roles in symptom induction and intercellular virus movement.

scholarly journals Tobacco rattle virus -induced gene silencing in Hevea brasiliensis

2020 ◽  
Author(s):  
Hui-Liang Li ◽  
Dong Guo ◽  
Ying Wang ◽  
Jia-Hong Zhu ◽  
Long Qu ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Hevea Brasiliensis ◽  
Rubber Tree ◽  
Tobacco Rattle Virus ◽  
Functional Gene ◽  
Small Interfering Rnas ◽  
Virus Induced Gene Silencing ◽  
Rubber Biosynthesis ◽  
Natural Rubber Biosynthesis ◽  
First Time

Abstract BackgroundSince it is very difficult to obtain gene knockouts in rubber tree (Hevea Brasiliensis) due to low genetic transformation efficiency. Virus-induced gene silencing (VIGS) is a powerful gene silencing tool that has been intensively applied in plant. Up to now, the application of VIGS in rubber tree has not yet been reported.ResultsHevea brasiliensis phytoene desaturase (HbPDS) was identified in H. brasiliensis genome. The prediction of small interfering RNAs (siRNAs) from HbPDS and the silencing gene fragment (SGF) were predicted and a length of 409 bp SGF was chosen to be tested. We show that the tobacco rattle virus (TRV) -VIGS is able to induce effective HbPDS silencing in rubber tree. The TRV-VIGS system has the potential for functional gene studies in rubber tree.ConclusionsThis is the first time to report VIGS in rubber tree. The present TRV-VIGS method could be further applied to produce gene silenced rubber tree plants, to advance functional gene of rubber tree. The applied TRV-VIGS method will achieve deeper underground into the natural rubber biosynthesis and regulation in this important rubber-producing plant.

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