RNA silencing plays an important antiviral role in plants and invertebrates. To counteract antiviral RNA silencing, most plant viruses have evolved viral suppressors of RNA silencing (VSRs). TRIPLE GENE BLOCK PROTEIN1 (TGBp1) of potexviruses is a well-characterized VSR, but the detailed mechanism by which it suppresses RNA silencing remains unclear. We demonstrate that transgenic expression of ...

In plants, small interfering RNAs (siRNAs) and microRNAs (miRNAs) are effectors of RNA silencing, a process involved in defense through RNA interference (RNAi) and in development. Plant viruses are natural targets of RNA silencing, and as a counterdefensive strategy, they have evolved highly diverse silencing suppressor proteins. Although viral suppressors are usually thought to act at distinct...

Recent advances in potexvirus research have produced new models describing virus replication, cell-to-cell movement, encapsidation, R gene-mediated resistance and gene silencing. Interactions between distant RNA elements are a central theme in potexvirus replication. The 5' non-translated region (NTR) regulates genomic and subgenomic RNA synthesis and encapsidation, as well as virus plasmodesma...

Posttranscriptional gene silencing (PTGS), or RNA silencing, is a sequence-specific RNA degradation process that targets foreign RNA, including viral and transposon RNA for destruction. Several RNA plant viruses have been shown to encode suppressors of PTGS in order to survive this host defense. We report here that the coat protein (CP) of Turnip crinkle virus (TCV) strongly suppresses PTGS. Th...

Plant viruses are inducers and targets of RNA silencing. Viruses counteract with RNA silencing by expressing silencing-suppressor proteins. Many of the identified proteins bind siRNAs, which prevents assembly of silencing effector complexes, and also interfere with their 3' methylation, which protects them against degradation. Here, we investigated the 3' modification of silencing-related small...

Post-transcriptional gene silencing is commonly observed in polyploid species and often poses a major limitation to plant improvement via biotechnology. Five plant viral suppressors of RNA silencing were evaluated for their ability to counteract gene silencing and enhance the expression of the Enhanced Yellow Fluorescent Protein (EYFP) or the β-glucuronidase (GUS) reporter gene in sugarcane, a ...

UNLABELLED The Cucumber Mosaic Virus (CMV) 2b protein is an RNA-silencing suppressor that plays roles in CMV accumulation and virulence. The 2b proteins of subgroup IA CMV strains partition between the nucleus and cytoplasm, but the biological significance of this is uncertain. We fused an additional nuclear localization signal (NLS) to the 2b protein of subgroup IA strain Fny-CMV to create 2b-...