Graft Transmission of RNA Silencing to Non-Transgenic Scions for Conferring Virus Resistance in Tobacco

The Cucumber mosaic virus (CMV)-encoded 2b protein (Cmv2b) is a nuclear protein that suppresses transgene RNA silencing in Nicotiana benthamiana. Cmv2b is an important virulence determinant but nonessential for systemic spread in N. glutinosa, in contrast to its indispensable role for systemic infections in cucumber. Here, we report that Cmv2b became essential for systemic infections in older N. glutinosa plants or in young seedlings pre-treated with salicylic acid (SA). Expression of Cmv2b from the genome of either CMV or Tobacco mosaic virus significantly reduced the inhibitory effect of SA on virus accumulation in inoculated leaves and systemic leaves. A close correlation is demonstrated between Cmv2b expression and a reduced SA-dependent induction of the alternative oxidase gene, a component of the recently proposed SA-regulated antiviral defense. These results collectively reveal a novel activity of Cmv2b in the inhibition of SA-mediated virus resistance. We used a N. tabacum line expressing a bacterial nahG transgene that degrades SA to provide evidence for a Cmv2b-sensitive antiviral defense mechanism in tobacco in which SA acts as a positive modifier but not as an essential component. We propose that SA induces virus resistance by potentiating a RNA-silencing antiviral defense that is targeted by Cmv2b.

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Different target genes and chimeric-gene hairpin structures affect virus resistance mediated by RNA silencing in transgenic tobacco

Biologia Plantarum ◽

10.1007/s10535-014-0422-9 ◽

2014 ◽

Vol 58 (3) ◽

pp. 575-581 ◽

Cited By ~ 2

Author(s):

X. Xie ◽

Y. Song ◽

X. Liu ◽

S. Wang ◽

C. Zhu ◽

...

Keyword(s):

Transgenic Tobacco ◽

Virus Resistance ◽

Rna Silencing ◽

Target Genes ◽

Chimeric Gene ◽

Hairpin Structures

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Multiple virus resistance at a high frequency using a single transgene construct

Journal of General Virology ◽

10.1099/vir.0.82276-0 ◽

2006 ◽

Vol 87 (12) ◽

pp. 3697-3701 ◽

Cited By ~ 115

Author(s):

Etienne Bucher ◽

Dick Lohuis ◽

Pieter M. J. A. van Poppel ◽

Christina Geerts-Dimitriadou ◽

Rob Goldbach ◽

...

Keyword(s):

Small Rna ◽

Virus Resistance ◽

High Frequency ◽

Rna Silencing ◽

Inverted Repeats ◽

Sequence Specificity ◽

Transgenic Expression ◽

Enhanced Resistance ◽

Multiple Virus ◽

Rna Fragments

RNA silencing is a natural antiviral defence in plants, which can be exploited in transgenic plants for preprogramming virus recognition and ensuring enhanced resistance. By arranging viral transgenes as inverted repeats it is thus possible to obtain strong repression of incoming viruses. Due to the high sequence specificity of RNA silencing, this technology has hitherto been limited to the targeting of single viruses. Here it is shown that efficient simultaneous targeting of four different tospoviruses can be achieved by using a single small transgene based on the production of minimal sized chimaeric cassettes. Due to simultaneous RNA silencing, as demonstrated by specific siRNA accumulation, the transgenic expression of these cassettes rendered up to 82 % of the transformed plant lines heritably resistant against all four viruses. Thus RNA silencing can be further improved for high frequency multiple virus resistance by combining small RNA fragments from a series of target viruses.

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Reprogramming of RNA silencing triggered by cucumber mosaic virus infection in Arabidopsis

Genome Biology ◽

10.1186/s13059-021-02564-z ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Maria Luz Annacondia ◽

German Martinez

Keyword(s):

Cucumber Mosaic Virus ◽

Mosaic Virus ◽

Virus Resistance ◽

Rna Silencing ◽

High Throughput Sequencing ◽

Small Interfering Rnas ◽

Genome Wide ◽

Endogenous Genes ◽

Silencing Pathways ◽

Relationship Of

Abstract Background RNA silencing has an important role mediating sequence-specific virus resistance in plants. The complex interaction of viruses with RNA silencing involves the loading of viral small interfering RNAs (vsiRNAs) into its host ARGONAUTE (AGO) proteins. As a side effect of their antiviral activity, vsiRNAs loading into AGO proteins can also mediate the silencing of endogenous genes. Here, we analyze at the genome-wide level both aspects of the interference of cucumber mosaic virus (CMV) with the RNA silencing machinery of Arabidopsis thaliana. Results We observe CMV-derived vsiRNAs affect the levels of endogenous sRNA classes. Furthermore, we analyze the incorporation of vsiRNAs into AGO proteins with a described antiviral role and the viral suppressor of RNA silencing (VSR) 2b, by combining protein immunoprecipitation with sRNA high-throughput sequencing. Interestingly, vsiRNAs represent a substantial percentage of AGO-loaded sRNAs and displace other endogenous sRNAs. As a countermeasure, the VSR 2b loaded vsiRNAs and mRNA-derived siRNAs, which affect the expression of the genes they derive from. Additionally, we analyze how vsiRNAs incorporate into the endogenous RNA silencing pathways by exploring their target mRNAs using parallel analysis of RNA end (PARE) sequencing, which allow us to identify vsiRNA-targeted genes genome-wide. Conclusions This work exemplifies the complex relationship of RNA viruses with the endogenous RNA silencing machinery and the multiple aspects of virus resistance and virulence that this interaction induces.

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Short interfering RNAs are Associated with Virus Resistance in a Woody Perennial Fruit Tree (Prunus domestica)

HortScience ◽

10.21273/hortsci.39.4.862d ◽

2004 ◽

Vol 39 (4) ◽

pp. 862D-862

Author(s):

Jean-Michel Hily ◽

Ralph Scorza* ◽

Michel Ravelonandro

Keyword(s):

Virus Resistance ◽

Rna Silencing ◽

Transcriptional Gene Silencing ◽

Marker Genes ◽

Plum Pox Virus ◽

Woody Perennials ◽

Woody Perennial ◽

Post Transcriptional Gene Silencing ◽

High Level ◽

Interfering Rna

We have shown that high-level resistance to plum pox virus (PPV) in transgenic plum clone C5 is based on post-transcriptional gene silencing (PTGS), otherwise termed RNA silencing (Scorza et al. Transgenic Res. 10:201-209, 2001). In order to more fully characterize RNA silencing in woody perennial crops, we investigated the production of short interfering RNA (siRNA) in transgenic plum clones C3 and C5, both of which harbor the capsid protein (CP) gene of PPV. We used as a control, plum PT-23, a clone only transformed with the two marker genes, NPTII and GUS. We show in the current report that C5 constitutively produces two classes of siRNA, the short (21-22 nucleotides) and long (≈27 nucleotides) species in the absence of PPV inoculation. Transgenic susceptible clone C3 and the control clone PT-23, when healthy, produce no siRNA. Upon infection, these clones produce only the short siRNA (21-22 nt). This siRNA production suggests that plum trees naturally respond to virus infection by initiating PTGS or PTGS-like mechanisms. This study also suggests that high-level virus resistance in woody perennials may require the production of both the short and long size classes of siRNA, as are produced by the resistant C5 plum clone.

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