RRC ID 74932
Author Sehki H, Yu A, Elmayan T, Vaucheret H.
Title TYMV and TRV infect Arabidopsis thaliana by expressing weak suppressors of RNA silencing and inducing host RNASE THREE LIKE1.
Journal PLoS Pathog
Abstract Post-Transcriptional Gene Silencing (PTGS) is a defense mechanism that targets invading nucleic acids of endogenous (transposons) or exogenous (pathogens, transgenes) origins. During plant infection by viruses, virus-derived primary siRNAs target viral RNAs, resulting in both destruction of single-stranded viral RNAs (execution step) and production of secondary siRNAs (amplification step), which maximizes the plant defense. As a counter-defense, viruses express proteins referred to as Viral Suppressor of RNA silencing (VSR). Some viruses express VSRs that totally inhibit PTGS, whereas other viruses express VSRs that have limited effect. Here we show that infection with the Turnip yellow mosaic virus (TYMV) is enhanced in Arabidopsis ago1, ago2 and dcl4 mutants, which are impaired in the execution of PTGS, but not in dcl2, rdr1 and rdr6 mutants, which are impaired in the amplification of PTGS. Consistently, we show that the TYMV VSR P69 localizes in siRNA-bodies, which are the site of production of secondary siRNAs, and limits PTGS amplification. Moreover, TYMV induces the production of the host enzyme RNASE THREE-LIKE 1 (RTL1) to further reduce siRNA accumulation. Infection with the Tobacco rattle virus (TRV), which also encodes a VSR limiting PTGS amplification, induces RTL1 as well to reduce siRNA accumulation and promote infection. Together, these results suggest that RTL1 could be considered as a host susceptibility gene that is induced by viruses as a strategy to further limit the plant PTGS defense when VSRs are insufficient.
Volume 19(1)
Pages e1010482
Published 2023-1-1
DOI 10.1371/journal.ppat.1010482
PMID 36696453
PMC PMC9901757
MeSH Arabidopsis* / genetics Arabidopsis* / metabolism Arabidopsis Proteins* / genetics Arabidopsis Proteins* / metabolism Mutation Plant Diseases* / genetics Plant Diseases* / virology RNA Interference RNA, Small Interfering / genetics RNA, Small Interfering / metabolism Repressor Proteins* / genetics Repressor Proteins* / metabolism Ribonuclease III / genetics Ribonuclease III / metabolism Tymovirus* / genetics Tymovirus* / metabolism
IF 6.218
Arabidopsis / Cultured plant cells, genes pst18958