The role of virus-derived small interfering RNAs in RNA silencing in plants

Abstract

Antiviral defense is one of the important roles of RNA silencing in plants. Virus-derived small interfering RNAs (vsiRNAs) are found in the infected host cells, indicating that the host RNA silencing machinery can target viral RNAs for destruction. With the development of high-throughput sequencing of vsiRNAs, recent genetic studies have shed light on the origin and composition of vsiRNAs and their potential functions in the regulation of gene expression. Here, we briefly describe the origin and biogenesis of vsiRNAs, and review the recent discoveries regarding vsiRNA-mediated RNA silencing of viral genomes and host transcripts. This will better our understanding of virus pathogenicity and RNA silencing-related host-pathogen interactions in plants.

Characterization of Small Interfering RNAs Derived from Sugarcane Mosaic Virus in Infected Maize Plants by Deep Sequencing

“…However, this could not explain the existence of hotspots and non-hotspots, because each position on the viral genome was a potential cleavage site in producing vsiRNA [40]. Moreover, the hotspots of sense and antisense strand were clustered in different regions of SCMV genome (Figure 3B).…”

“…It is unclear if all the vsiRNAs produced in the host cell can be incorporated into AGO-containing RISCs, and it remains to be established whether vsiRNAs can be recruited into all the AGO family members [40]. Recently, the findings from a research seemed to give us an answer that the majority of the vsiRNAs derived from TBSV were inefficient in guiding the formed RISC and specific vsiRNAs could be recruited into AGOs 1, 2, 3, 5, 7 and 10 of Arabidopsis , which were demonstrated to exhibit in vitro slicer activity [25].…”

“…To date, only a few studies have provided experimental evidence to verify the targeting of host genes, although many host transcripts potentially targeted by vsiRNAs have been predicted using bioinformatics [6], [7], [40]. Early studies suggested that some of the vsiRNAs may target host transcripts for post-transcriptional regulation by BLAST search and 5′ RACE [3], [41], [42].…”

Small RNAs were involved in homozygous state-associated silencing of a marker gene (Neomycin phosphotransferase II: nptII) in transgenic tomato plants

“…DCL4 cleaves dsRNA into 21-nt siRNAs which then guide the cleavage of target mRNA. DCL3 produces 24-nt siRNAs which triggers RNA-directed DNA methylation (RdDM) and then lead to TGS [39]. While DCL2 produces 22-nt siRNAs which trigger RdRP-mediated synthesis of RNA and result in amplification of RNAi [40].…”

Small RNA biology: From fundamental studies to applications

“…In plants, small RNAs can also be produced from invading exogenous nucleic acids such as viruses, and these virus-derived siRNAs target cognate RNAs for specific degradation [19,20]. If a recombinant virus harboring a sequence fragment of a plant gene, the cognate endogenous mRNAs can be degraded upon virus infection [21].…”