scholarly journals Self-interaction of the cucumber mosaic virus 2b protein plays a vital role in the suppression of RNA silencing and the induction of viral symptoms

2013 ◽  
Vol 14 (8) ◽  
pp. 803-812 ◽  
Author(s):  
Aixia Xu ◽  
Zhijing Zhao ◽  
Wenhu Chen ◽  
Hengmu Zhang ◽  
Qiansheng Liao ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
Vital Role ◽  
2B Protein

scholarly journals Symptom induction and RNA silencing suppression by the cucumber mosaic virus 2b protein

2010 ◽  
Vol 5 (6) ◽  
pp. 705-708 ◽  
Author(s):  
Mathew G. Lewsey ◽  
Inmaculada González ◽  
Natalia O. Kalinina ◽  
Peter Palukaitis ◽  
Tomas Canto ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
2B Protein ◽  
Silencing Suppression

scholarly journals The Weak Small RNA-Binding Activity of the 2b Proteins of Subgroup II Cucumber Mosaic Virus Strains Is Insufficient for RNA Silencing Suppression

2021 ◽  
Vol 12 ◽  
Author(s):  
Yingying Gao ◽  
Jinrui Yang ◽  
Xiaobei Zhang ◽  
Aizhong Chen ◽  
Zhouhang Gu ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
Rna Binding ◽  
Nuclear Accumulation ◽  
Nuclear Localization Sequence ◽  
Binding Ability ◽  
Suppressor Activity ◽  
Subgroup Ii ◽  
2B Protein

The 2b proteins encoded by cucumber mosaic virus (CMV) subgroup I strains suppress RNA silencing primarily by competitively binding small RNAs (sRNAs) in the host cell cytoplasm. Interestingly, 2b proteins encoded by CMV subgroup II strains accumulate predominantly in nuclei. Here we determined that whereas the 2b protein (Fny2b) of subgroup IA strain Fny-CMV is highly effective in suppressing both sense RNA-induced and inverted repeat-induced posttranscriptional gene silencing, the 2b protein (LS2b) of the subgroup II strain LS-CMV was not as effective. Reducing nuclear accumulation of LS2b by mutating a residue in its nuclear localization sequence had no effect on RNA silencing suppressor activity, while attenuated viral symptoms. Electrophoretic mobility shift assays showed that the sRNA binding of LS2b was weaker and more selective than that of Fny2b. The domain determining the differential sRNA-binding ability was delimited to the putative helix α1 region. Moreover, LS2b mutants that completely lost suppressor activity still retained their weak sRNA-binding ability, suggesting that sRNA binding is not sufficient for LS2b to suppress RNA silencing. Considering the subgroup I strain-encoded 2b proteins that require sRNA-binding ability for the suppression of RNA silencing, we suggest that in addition to binding sRNA, the 2b proteins of subgroup II CMV strains would require extra biological activities to achieve RNA silencing inhibition.

Effects of the 2b Protein of Cucumber mosaic virus Subgroup IB Strain IA on Different Transgene-Induced RNA Silencing Pathways

2017 ◽  
Vol 35 (2) ◽  
pp. 265-272 ◽  
Author(s):  
Mayuko Koizumi ◽  
Yumi Shimotori ◽  
Yuta Saeki ◽  
Sayaka Hirai ◽  
Shin-ichiro Oka ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
2B Protein ◽  
Silencing Pathways

scholarly journals The 2b protein of cucumber mosaic virus is essential for viral infection of the shoot apical meristem and for efficient invasion of leaf primordia in infected tobacco plants

2009 ◽  
Vol 90 (12) ◽  
pp. 3015-3021 ◽  
Author(s):  
Anurag Sunpapao ◽  
Takashi Nakai ◽  
Fang Dong ◽  
Tomofumi Mochizuki ◽  
Satoshi T. Ohki
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Shoot Apical Meristem ◽  
Rna Silencing ◽  
Apical Meristem ◽  
Leaf Primordia ◽  
Shoot Meristem ◽  
Tobacco Plants ◽  
2B Protein ◽  
Infected Tobacco

It has been reported previously that a 2b protein-defective mutant of the cucumber mosaic virus (CMV) Pepo strain (Δ2b) induces only mild symptoms in systemically infected tobacco plants. To clarify further the role of the 2b protein as an RNA silencing suppressor in mosaic symptom expression during CMV infection, this study monitored the sequential distribution of Δ2b in the shoot meristem and leaf primordia (LP) of inoculated tobacco. Time-course histochemical observations revealed that Δ2b was distributed in the shoot meristem at 7 days post-inoculation (p.i.), but could not invade shoot apical meristem (SAM) and quickly disappeared from the shoot meristem, whereas wild-type (Pepo) transiently appeared in SAM from 4 to 10 days p.i. In LP, Δ2b signals were detected only at 14 and 21 days p.i., whereas dense Pepo signals were observed in LP from 4 to 18 days p.i. Northern blot analysis showed that small interfering RNA (siRNA) derived from Δ2b RNA accumulated earlier in the shoot meristem and LP than that of Pepo. However, a similar amount of siRNA was detected in both Pepo- and Δ2b-infected plants at late time points. Tissue printing analysis of the inoculated leaves indicated that the areas infected by Pepo increased faster than those infected by Δ2b, whereas accumulation of Δ2b in protoplasts was similar to that of Pepo. These findings suggest that the 2b protein of the CMV Pepo strain determines virulence by facilitating the distribution of CMV in the shoot meristem and LP via prevention of RNA silencing and/or acceleration of cell-to-cell movement.

Cucumber mosaic virus 2b protein inhibits RNA silencing pathways in green alga Chlamydomonas reinhardtii

2010 ◽  
Vol 29 (9) ◽  
pp. 967-975 ◽  
Author(s):  
Joon-Woo Ahn ◽  
Chun-Ji Yin ◽  
Jang Ryol Liu ◽  
Won-Joong Jeong
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Green Alga ◽  
Rna Silencing ◽  
2B Protein ◽  
Silencing Pathways

scholarly journals Cucumber Mosaic Virus 2b Protein Subcellular Targets and Interactions: Their Significance to RNA Silencing Suppressor Activity

2010 ◽  
Vol 23 (3) ◽  
pp. 294-303 ◽  
Author(s):  
Inmaculada González ◽  
Llucia Martínez ◽  
Daria V. Rakitina ◽  
Mathew G. Lewsey ◽  
Félix A. Atencio ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Small Rnas ◽  
Rna Silencing ◽  
Silencing Suppressor ◽  
Suppressor Activity ◽  
Rna Silencing Suppressor ◽  
2B Protein

The RNA silencing suppressor activity of the 2b protein of Cucumber mosaic virus (CMV) has been variously attributed to its nuclear targeting, its interaction with and inhibition of Argonaute 1 (AGO1), or its ability to bind small RNAs in vitro. In addition, the 2b ortholog of Tomato aspermy virus forms aggregates and binds RNAs in vitro. We have further studied the relationships between CMV 2b protein silencing suppressor activity and its subcellular distribution, protein-protein interactions in vivo, and interactions with small interfering RNAs in vitro. To do this, we tagged the protein with fluorescent markers and showed that it retained suppressor activity. We showed that the 2b protein is present in the nucleolus and that it self-interacts and interacts with AGO1 and AGO4 in vivo. Using a battery of mutants, we showed that the putative nuclear localization signals and phosphorylation motif of the 2b protein are not required for self-interaction or for interaction with AGO proteins. The occurrence of neither of these interactions or of nucleolar targeting was sufficient to provide local silencing-suppression activity. In contrast, the ability of the 2b protein to bind small RNAs appears to be indispensable for silencing suppressor function.

scholarly journals Suppression of Arabidopsis ARGONAUTE1-Mediated Slicing, Transgene-Induced RNA Silencing, and DNA Methylation by Distinct Domains of the Cucumber mosaic virus 2b Protein

2012 ◽  
Vol 24 (1) ◽  
pp. 259-274 ◽  
Author(s):  
Cheng-Guo Duan ◽  
Yuan-Yuan Fang ◽  
Bang-Jun Zhou ◽  
Jian-Hua Zhao ◽  
Wei-Na Hou ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
2B Protein

scholarly journals Analysis of Mechanisms Involved in the Cucumber mosaic virus Satellite RNA-mediated Transgenic Resistance in Tomato Plants

2004 ◽  
Vol 17 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Fabrizio Cillo ◽  
Mariella M. Finetti-Sialer ◽  
Maria A. Papanice ◽  
Donato Gallitelli
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
Resistance Mechanism ◽  
Degradation Process ◽  
Transgenic Tomato ◽  
Satellite Rna ◽  
Total Recovery ◽  
Tomato Plants ◽  
Free Strain

Transgenic tomato (Lycopersicon esculentum Mill. cv. UC82) plants expressing a benign variant of Cucumber mosaic virus satellite RNA (CMV Tfn-satRNA) were generated. The transformed plants did not produce symptoms when challenged with a satRNA-free strain of CMV (CMV-FL). The same plant lines initially were susceptible to necrosis elicited by a CMV strain supporting a necrogenic variant of satRNA (CMV-77), but a phenotype of total recovery from the necrosis was observed in the newly developing leaves. The features of the observed resistance were analyzed and are consistent with two different mechanisms of resistance. In transgenic plants inoculated with CMV-FL strain, the symptomless phenotype was correlated to the down-regulation of CMV by Tfn-satRNA, amplified from the transgene transcripts, as the first resistance mechanism. On the other hand, the delayed resistance to CMV-77 in transgenic tomato lines was mediated by a degradation process that targets satRNAs in a sequence-specific manner. Evidence is provided for a correlation between a reduced accumulation level of transgenic messenger Tfn-satRNA, the accumulation of small (approximately 23 nucleotides) RNAs with sequence homology to satRNAs, the progressively reduced accumulation of 77-satRNA in infected tissues, and the transition in infected plants from diseased to healthy. Thus, events leading to the degradation of satRNA sequences indicate a role for RNA silencing as the second mechanism determining resistance of transgenic tomato lines.

scholarly journals Cucumber mosaic virus and its 2b RNA silencing suppressor modify plant-aphid interactions in tobacco

2011 ◽  
Vol 1 (1) ◽  
Author(s):  
Heiko Ziebell ◽  
Alex M. Murphy ◽  
Simon C. Groen ◽  
Trisna Tungadi ◽  
Jack H. Westwood ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
Silencing Suppressor ◽  
Rna Silencing Suppressor

scholarly journals The Suppressor of Transgene RNA Silencing Encoded by Cucumber mosaic virus Interferes with Salicylic Acid-Mediated Virus Resistance

2001 ◽  
Vol 14 (6) ◽  
pp. 715-724 ◽  
Author(s):  
Liang-Hui Ji ◽  
Shou-Wei Ding
Keyword(s):  
Salicylic Acid ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Virus Resistance ◽  
Rna Silencing ◽  
Defense Mechanism ◽  
Antiviral Defense ◽  
Oxidase Gene ◽  
Systemic Spread ◽  
Systemic Infections

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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