Diverse conserved domains and a positively selected site in the sugarcane streak mosaic virus P1 protein are essential for RNA silencing suppression and protein stability

2020 ◽  
Vol 69 (7) ◽  
pp. 1390-1400
Author(s):  
Jian‐Sheng Chen ◽  
Shan‐Shan Liang ◽  
Sheng‐Ren Sun ◽  
Mona B. Damaj ◽  
Hua‐Ying Fu ◽  
...  
2014 ◽  
Vol 27 (9) ◽  
pp. 944-955 ◽  
Author(s):  
Yi-Jung Kung ◽  
Pin-Chun Lin ◽  
Shyi-Dong Yeh ◽  
Syuan-Fei Hong ◽  
Nam-Hai Chua ◽  
...  

Cross-protection triggered by a mild strain of virus acts as a prophylaxis to prevent subsequent infections by related viruses in plants; however, the underling mechanisms are not fully understood. Through mutagenesis, we isolated a mutant strain of Turnip mosaic virus (TuMV), named Tu-GK, that contains an Arg182Lys substitution in helper component-proteinase (HC-ProK) that confers complete cross-protection against infection by a severe strain of TuMV in Nicotiana benthamiana, Arabidopsis thaliana Col-0, and the Arabidopsis dcl2-4/dcl4-1 double mutant defective in DICER-like ribonuclease (DCL)2/DCL4-mediated silencing. Our analyses showed that HC-ProK loses the ability to interfere with microRNA pathways, although it retains a partial capability for RNA silencing suppression triggered by DCL. We further showed that Tu-GK infection triggers strong salicylic acid (SA)-dependent and SA-independent innate immunity responses. Our data suggest that DCL2/4-dependent and –independent RNA silencing pathways are involved, and may crosstalk with basal innate immunity pathways, in host defense and in cross-protection.


2010 ◽  
Vol 5 (6) ◽  
pp. 705-708 ◽  
Author(s):  
Mathew G. Lewsey ◽  
Inmaculada González ◽  
Natalia O. Kalinina ◽  
Peter Palukaitis ◽  
Tomas Canto ◽  
...  

2012 ◽  
Vol 25 (5) ◽  
pp. 648-657 ◽  
Author(s):  
Li-Ya Wang ◽  
Shih-Shun Lin ◽  
Ting-Hsuan Hung ◽  
Tsai-Kun Li ◽  
Nai-Chun Lin ◽  
...  

Small RNA-mediated RNA silencing is a widespread antiviral mechanism in plants and other organisms. Many viruses encode suppressors of RNA silencing for counter-defense. The p126 protein encoded by Tobacco mosaic virus (TMV) has been reported to be a suppressor of RNA silencing but the mechanism of its function remains unclear. This protein is unique among the known plant viral silencing suppressors because of its large size and multiple domains. Here, we report that the methyltransferase, helicase, and nonconserved region II (NONII) of p126 each has silencing-suppressor function. The silencing-suppression activities of methyltransferase and helicase can be uncoupled from their enzyme activities. Specific amino acids in NONII previously shown to be crucial for viral accumulation and symptom development are also crucial for silencing suppression. These results suggest that some viral proteins have evolved to possess modular structural domains that can independently interfere with host silencing, and that this may be an effective mechanism of increasing the robustness of a virus.


Virus Genes ◽  
2016 ◽  
Vol 52 (4) ◽  
pp. 592-596 ◽  
Author(s):  
Jae-Yeong Han ◽  
Jinsoo Chung ◽  
Jungkyu Kim ◽  
Eun-Young Seo ◽  
James P. Kilcrease ◽  
...  

2020 ◽  
Vol 11 ◽  
Author(s):  
Xiao-Jie Xu ◽  
Huan-Gai Li ◽  
De-Jie Cheng ◽  
Ling-Zhi Liu ◽  
Chao Geng ◽  
...  

2012 ◽  
Vol 93 (8) ◽  
pp. 1841-1850 ◽  
Author(s):  
Ida Bagus Andika ◽  
Hideki Kondo ◽  
Masamichi Nishiguchi ◽  
Tetsuo Tamada

Many plant viruses encode proteins that suppress RNA silencing, but little is known about the activity of silencing suppressors in roots. This study examined differences in the silencing suppression activity of different viruses in leaves and roots of Nicotiana benthamiana plants. Infection by tobacco mosaic virus, potato virus Y and cucumber mosaic virus but not potato virus X (PVX) resulted in strong silencing suppression activity of a transgene in both leaves and roots, whereas infection by beet necrotic yellow vein virus (BNYVV) and tobacco rattle virus (TRV) showed transgene silencing suppression in roots but not in leaves. For most viruses tested, viral negative-strand RNA accumulated at a very low level in roots, compared with considerable levels of positive-strand genomic RNA. Co-inoculation of leaves with PVX and either BNYVV or TRV produced an increase in PVX negative-strand RNA and subgenomic RNA (sgRNA) accumulation in roots. The cysteine-rich proteins (CRPs) BNYVV p14 and TRV 16K showed weak silencing suppression activity in leaves. However, when either of these CRPs was expressed from a PVX vector, there was an enhancement of PVX negative-strand RNA and sgRNA accumulation in roots compared with PVX alone. Such enhancement of PVX sgRNAs was also observed by expression of CRPs of other viruses and the well-known suppressors HC-Pro and p19 but not of the potato mop-top virus p8 CRP. These results indicate that BNYVV- and TRV-encoded CRPs suppress RNA silencing more efficiently in roots than in leaves.


2014 ◽  
Vol 159 (6) ◽  
pp. 1373-1383 ◽  
Author(s):  
Mei-Jia Li ◽  
Jung-Kyu Kim ◽  
Eun-Young Seo ◽  
Seok Myeong Hong ◽  
Eui-Il Hwang ◽  
...  

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