scholarly journals Identification of an RNA silencing suppressor encoded by a mastrevirus

2014 ◽  
Vol 95 (9) ◽  
pp. 2082-2088 ◽  
Author(s):  
Yaqin Wang ◽  
Mingqing Dang ◽  
Huwei Hou ◽  
Yuzhen Mei ◽  
Yajuan Qian ◽  
...  

Wheat dwarf virus (WDV) is a DNA virus belonging to the genus Mastrevirus of the family Geminiviridae. In this study, we report that the Rep protein encoded by WDV is a RNA silencing supressor as determined by co-infiltration assays using transgenic Nicotiana benthamiana line 16c carrying the GFP reporter gene. The Rep protein was shown to inhibit both local and systemic RNA silencing of the GFP gene as well as the spread of systemic GFP RNA silencing signals. Gel mobility shift assays showed that the Rep protein binds 21 nt and 24 nt small interfering RNA (siRNA) duplexes and single-stranded (ss)-siRNA. To our knowledge, this is the first identification of an RNA silencing suppressor encoded by mastreviruses. Furthermore, deletion mutagenesis indicates that both the N- and C-terminal regions of the Rep protein are not critical for silencing suppression and self-interaction, but the N terminus of Rep is necessary for its pathogenicity.

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1111
Author(s):  
Chen-Wei Zhang ◽  
Qing Liu ◽  
Qi Zeng ◽  
Wen-Ting Huang ◽  
Qi Wang ◽  
...  

Grapevine leafroll-associated virus 1 (GLRaV-1) is a major pathogen associated with grapevine leafroll disease. However, the molecular mechanisms underlying GLRaV-1 interactions with plant cells are unclear. Using Agrobacterium infiltration-mediated RNA-silencing assays, we demonstrated that GLRaV-1 p24 protein (p24G1) acts as an RNA-silencing suppressor (RSS), inhibiting local and systemic RNA silencing. Electrophoretic mobility shift assays showed that p24G1 binds double-stranded 21-nucleotide small interfering RNA (siRNA), and that siRNA binding is required but not sufficient for its RSS activity. p24G1 localizes in the nucleus and can self-interact through its amino acid 10 to 210 region. Dimerization is needed for p24G1 interaction with importin α1 before moving to the nucleus, but is not required for its siRNA binding and RSS activity. Expression of p24G1 from a binary pGD vector or potato virus X-based vector elicited a strong hypersensitive response in Nicotiana species, indicating that p24G1 may be a factor in pathogenesis. Furthermore, p24G1 function in pathogenesis required its RSS activity, dimerization and nuclear localization. In addition, the region of amino acids 122–139 played a crucial role in the nuclear import, siRNA binding, silencing suppression and pathogenic activity of p24G1. These results contribute to our understanding of the molecular mechanisms underlying GLRaV-1 infection.


2009 ◽  
Vol 36 (5) ◽  
pp. 541-548 ◽  
Author(s):  
Li LIU ◽  
Jian LI ◽  
Yu-Ping XU ◽  
Wen-Tao QIAO ◽  
Qi-Min CHEN ◽  
...  

Plant Biology ◽  
2021 ◽  
Author(s):  
Licheng Wang ◽  
Wenbao Chen ◽  
Huan Ma ◽  
Jingyuan Li ◽  
Xingan Hao ◽  
...  

Virology ◽  
2019 ◽  
Vol 526 ◽  
pp. 45-51 ◽  
Author(s):  
Quan-You Lu ◽  
Lei Yang ◽  
Jinshan Huang ◽  
Luping Zheng ◽  
Xin Sun

2008 ◽  
Vol 82 (23) ◽  
pp. 11851-11858 ◽  
Author(s):  
Vitantonio Pantaleo ◽  
József Burgyán

ABSTRACT Cymbidium ringspot virus (CymRSV) satellite RNA (satRNA) is a parasitic subviral RNA replicon that replicates and accumulates at the cost of its helper virus. This 621-nucleotide (nt) satRNA species has no sequence similarity to the helper virus, except for a 51-nt-long region termed the helper-satellite homology (HSH) region, which is essential for satRNA replication. We show that the accumulation of satRNA strongly depends on temperature and on the presence of the helper virus p19 silencing suppressor protein, suggesting that RNA silencing plays a crucial role in satRNA accumulation. We also demonstrate that another member of the Tombusvirus genus, Carnation Italian ringspot virus (CIRV), supports satRNA accumulation at a higher level than CymRSV. Our results suggest that short interfering RNA (siRNA) derived from CymRSV targets satRNA more efficiently than siRNA from CIRV, possibly because of the higher sequence similarity between the HSH regions of the helper and CIRV satRNAs. RNA silencing sensor RNA carrying the putative satRNA target site in the HSH region was efficiently cleaved when transiently expressed in CymRSV-infected plants but not in CIRV-infected plants. Strikingly, replacing the CymRSV HSH box2 sequence with that of CIRV restores satRNA accumulation both at 24°C and in the absence of the p19 suppressor protein. These findings demonstrate the extraordinary adaptation of this virus to its host in terms of harnessing the antiviral silencing response of the plant to control the virus parasite satRNA.


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