scholarly journals Cytorhabdovirus P protein suppresses RISC-mediated cleavage and RNA silencing amplification in planta

Virology ◽  
2016 ◽  
Vol 490 ◽  
pp. 27-40 ◽  
Author(s):  
Krin S. Mann ◽  
Karyn N. Johnson ◽  
Bernard J. Carroll ◽  
Ralf G. Dietzgen
Keyword(s):  
Rna Silencing ◽  
In Planta ◽  
P Protein

scholarly journals Complete Genome Sequence and In Planta Subcellular Localization of Maize Fine Streak Virus Proteins

2005 ◽  
Vol 79 (9) ◽  
pp. 5304-5314 ◽  
Author(s):  
Chi-Wei Tsai ◽  
Margaret G. Redinbaugh ◽  
Kristen J. Willie ◽  
Sharon Reed ◽  
Michael Goodin ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Protein Interactions ◽  
Matrix Protein ◽  
Fluorescent Protein ◽  
Streak Virus ◽  
In Planta ◽  
Nuclear Localization Signals ◽  
N Protein ◽  
P Protein ◽  
Maize Fine Streak Virus

ABSTRACT The genome of the nucleorhabdovirus maize fine streak virus (MFSV) consists of 13,782 nucleotides of nonsegmented, negative-sense, single-stranded RNA. The antigenomic strand consisted of seven open reading frames (ORFs), and transcripts of all ORFs were detected in infected plants. ORF1, ORF6, and ORF7 had significant similarities to the nucleocapsid protein (N), glycoprotein (G), and polymerase (L) genes of other rhabdoviruses, respectively, whereas the ORF2, ORF3, ORF4, and ORF5 proteins had no significant similarities. The N (ORF1), ORF4, and ORF5 proteins localized to nuclei, consistent with the presence of nuclear localization signals (NLSs) in these proteins. ORF5 likely encodes the matrix protein (M), based on its size, the position of its NLS, and the localization of fluorescent protein fusions to the nucleus. ORF2 probably encodes the phosphoprotein (P) because, like the P protein of Sonchus yellow net virus (SYNV), it was spread throughout the cell when expressed alone but was relocalized to a subnuclear locus when coexpressed with the MFSV N protein. Unexpectedly, coexpression of the MFSV N and P proteins, but not the orthologous proteins of SYNV, resulted in accumulations of both proteins in the nucleolus. The N and P protein relocalization was specific to cognate proteins of each virus. The subcellular localizations of the MFSV ORF3 and ORF4 proteins were distinct from that of the SYNV sc4 protein, suggesting different functions. To our knowledge, this is the first comparative study of the cellular localizations of plant rhabdoviral proteins. This study indicated that plant rhabdoviruses are diverse in genome sequence and viral protein interactions.

RNA silencing and its suppression: novel insights from in planta analyses

2013 ◽  
Vol 18 (7) ◽  
pp. 382-392 ◽  
Author(s):  
Marco Incarbone ◽  
Patrice Dunoyer
Keyword(s):  
Rna Silencing ◽  
In Planta

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-spray-mediated silencing of Fusarium graminearum AGO and DCL genes improve barley disease resistance

2019 ◽  
Author(s):  
B Werner ◽  
FY Gaffar ◽  
J Schuemann ◽  
D Biedenkopf ◽  
A Koch
Keyword(s):  
Gene Silencing ◽  
Fusarium Graminearum ◽  
Rna Silencing ◽  
Molecular Mechanisms ◽  
Plant Protection ◽  
Future Application ◽  
In Planta ◽  
Plant Host ◽  
Barley Leaves ◽  
Potential Alternative

AbstractOver the last decade, several studies have revealed the enormous potential of RNA-silencing strategies as a potential alternative to conventional pesticides for plant protection. We have previously shown that targeted gene silencing mediated by an in planta expression of non-coding inhibitory double-stranded RNAs (dsRNAs) can protect host plants against various diseases with unprecedented efficiency. In addition to the generation of RNA-silencing (RNAi) signals in planta, plants can be protected from pathogens and pests by spray-applied RNA-based biopesticides. Despite the striking efficiency of RNA-silencing-based technologies holds for agriculture, the molecular mechanisms underlying spray-induced gene silencing (SIGS) strategies are virtually unresolved, a requirement for successful future application in the field. Based on our previous work, we predict that the molecular mechanism of SIGS is controlled by the fungal-silencing machinery. In this study, we used SIGS to compare the silencing efficiencies of computationally-designed versus manually-designed dsRNA constructs targeting ARGONAUTE and DICER genes of Fusarium graminearum (Fg). We found that targeting key components of the fungal RNAi machinery via SIGS could protect barley leaves from Fg infection and that the manual design of dsRNAs resulted in higher gene-silencing efficiencies than the tool-based design. Moreover, our results indicate the possibility of cross-kingdom RNA silencing in the Fg-barley interaction, a phenomenon in which sRNAs operate as effector molecules to induce gene silencing between species from different kingdoms, such as a plant host and their interacting pathogens.

scholarly journals The p122 Subunit of Tobacco Mosaic Virus Replicase Is a Potent Silencing Suppressor and Compromises both Small Interfering RNA- and MicroRNA-Mediated Pathways

2007 ◽  
Vol 81 (21) ◽  
pp. 11768-11780 ◽  
Author(s):  
Tibor Csorba ◽  
Aurelie Bovi ◽  
Tamás Dalmay ◽  
József Burgyán
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Nuclear Export ◽  
Rna Silencing ◽  
Plant Viruses ◽  
Silencing Suppressor ◽  
Small Interfering Rnas ◽  
In Planta ◽  
Interfering Rna

ABSTRACT One of the functions of RNA silencing in plants is to defend against molecular parasites, such as viruses, retrotransposons, and transgenes. Plant viruses are inducers, as well as targets, of RNA silencing-based antiviral defense. Replication intermediates or folded viral RNAs activate RNA silencing, generating small interfering RNAs (siRNAs), which are the key players in the antiviral response. Viruses are able to counteract RNA silencing by expressing silencing-suppressor proteins. It has been shown that many of the identified silencing-suppressor proteins bind long double-stranded RNA or siRNAs and thereby prevent assembly of the silencing effector complexes. In this study, we show that the 122-kDa replicase subunit (p122) of crucifer-infecting Tobacco mosaic virus (cr-TMV) is a potent silencing-suppressor protein. We found that the p122 protein preferentially binds to double-stranded 21-nucleotide (nt) siRNA and microRNA (miRNA) intermediates with 2-nt 3′ overhangs inhibiting the incorporation of siRNA and miRNA into silencing-related complexes (e.g., RNA-induced silencing complex [RISC]) both in vitro and in planta but cannot interfere with previously programmed RISCs. In addition, our results also suggest that the virus infection and/or sequestration of the siRNA and miRNA molecules by p122 enhances miRNA accumulation despite preventing its methylation. However, the p122 silencing suppressor does not prevent the methylation of certain miRNAs in hst-15 mutants, in which the nuclear export of miRNAs is compromised.

scholarly journals In Planta Recognition of a Double-Stranded RNA Synthesis Protein Complex by a Potexviral RNA Silencing Suppressor

2014 ◽  
Vol 26 (5) ◽  
pp. 2168-2183 ◽  
Author(s):  
Yukari Okano ◽  
Hiroko Senshu ◽  
Masayoshi Hashimoto ◽  
Yutaro Neriya ◽  
Osamu Netsu ◽  
...  
Keyword(s):  
Protein Complex ◽  
Rna Silencing ◽  
Rna Synthesis ◽  
Silencing Suppressor ◽  
In Planta ◽  
Double Stranded Rna ◽  
Rna Silencing Suppressor

scholarly journals In vitro identification and in vivo confirmation of inhibitors for SPCSV RNA silencing suppressor, a viral RNase III

2021 ◽  
Author(s):  
Linping Wang ◽  
Sylvain Poque ◽  
Karoliina Laamanen ◽  
Jani Saarela ◽  
Antti Poso ◽  
...  
Keyword(s):  
Sweet Potato ◽  
High Throughput ◽  
Rna Silencing ◽  
Yield Loss ◽  
Virus Disease ◽  
Silencing Suppressor ◽  
In Planta ◽  
Rnase Iii ◽  
Rna Silencing Suppressor ◽  
Viral Accumulation

Sweet potato virus disease (SPVD), caused by synergistic infection of Sweet potato chlorotic stunt virus (SPCSV) and Sweet potato feathery mottle virus (SPFMV), is responsible for substantial yield loss all over the world. However, there are currently no approved treatments for this severe disease. The crucial role played by RNase III of SPCSV (CSR3) as RNA silencing suppressor during the viruses' synergistic interaction in sweetpotato makes it an ideal drug target for developing antiviral treatment. In this study, high-throughput screening (HTS) of small molecular libraries targeting CSR3 was initiated by a virtual screen using Glide-docking, allowing the selection of 6,400 compounds out of 136,353. We subsequently developed and carried out a kinetic-based HTS using fluorescence resonance energy transfer technology that isolated 112 compounds. These compounds were validated with dose-response assays including the kinetic-based HTS and binding affinity assays using surface plasmon resonance and microscale thermophoresis. Finally, the interference of the selected compounds with viral accumulation was verified in planta. In summary, we identified five compounds belonging to two structural classes that inhibited CSR3 activity and reduced viral accumulation in plants. These results provide the foundation for developing antiviral agents targeting CSR3 to provide new strategies for controlling sweetpotato virus diseases. Significance statement We report here a high-throughput inhibitor identification that targets a severe sweetpotato virus disease caused by co-infection with two viruses (SPCSV and SPFMV). The disease is responsible for up to 90% yield loss. Specifically, we targeted the RNase III enzyme encoded by SPCSV, which plays an important role in suppressing the RNA silencing defense system of sweetpotato plants. Based on virtual screening, laboratory assays, and confirmation in planta, we identified five compounds that could be used to develop antiviral drugs to combat the most severe sweetpotato virus disease.

The Fine Structure of Phloem Cells

1985 ◽  
Vol 43 ◽  
pp. 632-635
Author(s):  
James Cronshaw
Keyword(s):  
Structural Studies ◽  
High Concentration ◽  
Long Distance ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Electron Microscopical ◽  
Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

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