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

Zhanbiao Li,Tong Zhang,Guohui Zhou,Xiuqin Huang

doi:10.3390/v10110594

Zhanbiao Li, Tong Zhang + Show 2 more

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https://doi.org/10.3390/v10110594

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Journal: Viruses	Publication Date: Oct 30, 2018
Citations: 10	License type: CC BY 4.0

Affiliation: South China Agricultural University

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.

Highlights

RNA silencing ( called RNA interference (RNAi)) in plants can function as an antiviral defense mechanism against invading viruses
Previous studies revealed that co-infection of maize by Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV) or co-infection of tobacco by Brassica yellows virus (BrYV, a provisional name) and Pea enation mosaic virus 2 (PEMV 2) increased the accumulation of both of the two viruses’ virus-derived interfering RNA (vsiRNA) compared with that seen in individual infections of the viruses
The results showed that the vsiRNAs from Southern rice black-streaked dwarf virus (SRBSDV) singly infected plants (474,032 reads) were significantly fewer than vsiRNAs from Rice ragged stunt virus (RRSV) singly infected plants

Summary

Introduction

RNA silencing ( called RNA interference (RNAi)) in plants can function as an antiviral defense mechanism against invading viruses. Previous studies revealed that co-infection of maize by Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV) or co-infection of tobacco by Brassica yellows virus (BrYV, a provisional name) and Pea enation mosaic virus 2 (PEMV 2) increased the accumulation of both of the two viruses’ vsiRNAs compared with that seen in individual infections of the viruses. This indicates that the effects on the RNAi pathway may differ between co-infection and individual infection by the viruses, and may play an important role in the viruses’ synergism [4,5]

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