Impact of Two Reoviruses and Their Coinfection on the Rice RNAi System and vsiRNA Production

Abstract

Both Southern rice black-streaked dwarf virus (SRBSDV) and Rice ragged stunt virus (RRSV) belong to the family Reoviridae, and synergistic infection of these two viruses commonly occurs in the field. This study revealed that both SRBSDV and RRSV affect the RNA interference (RNAi) pathway and form different virus-derived interfering RNA (vsiRNA) profiles in rice. Co-infection of rice by SRBSDV and RRSV up-regulated the expression of rice DICER-like (DCL) proteins but down-regulated the expression of rice RNA-dependent RNA polymerases (RDRs), and the accumulation of vsiRNAs of either RBSDV or RRSV was decreased compared with that in singly infected plants. The majority of SRBSDV vsiRNAs were 21 nt or 22 nt in length, whether plants were singly infected with SRBSDV or co-infected with RRSV. On the other hand, the majority of RRSV vsiRNAs were 20 nt, 21 nt, or 22 nt in length, among which those 20 nt in length accounted for the largest proportion; co-infection with SRBSDV further increased the proportion of 20 nt vsiRNAs and decreased the proportion of 21 nt vsiRNAs. Co-infection had no effects on the strand favoritism and hot spots of the vsiRNAs, but changed the bias of the 5′ terminal nucleotide significantly. This study provides a reference for further study on the pathogenesis and synergistic mechanism of SRBSDV and RRSV.

Metatranscriptomic Sequencing Suggests the Presence of Novel RNA Viruses in Rice Transmitted by Brown Planthopper

“…RRSV vsiRNAs also showed a strong sense strand bias in Rby1-21 and Rby2-45, suggesting RRSV-derived vsiRNA originated from highly structured single-stranded viral RNA. Similar results were observed in singly (RRSV) or doubly (RRSV and SRBSDV) virusinfected rice plants [30]. Taken together, our results strongly suggest rice-plant-encoded, DICER-like enzymes recognize highly structured regions RTV1 and RRSV viral ssRNAs and process them into siRNAs.…”

Rice Stripe Virus Coat Protein-Mediated Virus Resistance Is Associated With RNA Silencing in Arabidopsis

“…In RSV-infected Arabidopsis, 20nt vsiRNAs was the most abundant species (Figure 3B). This result is similar to the rice ragged stunt virus (RRSV) vsiRNAs in rice plants (Li et al, 2018). In RSV-infected rice and tobacco plants, 20 nt vsiRNAs also account for the high proportion (Yan et al, 2010;Jiang et al, 2012;Xu et al, 2012).…”

Resistance Evaluation of Dominant Varieties against Southern Rice Black-Streaked Dwarf Virus in Southern China

“…At 15 dpi, 30 dpi, and 45 dpi, tissues from the second developed upper leaf of infected and healthy plants were sampled and detected via RT-qPCR [ 15 ] and Western blot [ 16 ] for the SRBSDV titer. At least five infected and healthy plants were detected for each variety, and the relative virus accumulation level was determined by the 2 delta–delta Ct method and t-test analysis or one-way ANOVA SPSS19.0 software (IBM, New York, NY, USA).…”