title: A mycoreovirus suppresses RNA silencing in the white root rot fungus, Rosellinia necatrix.
abstract: RNA silencing is a fundamental antiviral response in eukaryotic organisms. We investigated the counterdefense strategy of a fungal virus (mycovirus) against RNA silencing in the white root rot fungus, Rosellinia necatrix. We generated an R. necatrix strain that constitutively induced RNA silencing of the exogenous green fluorescent protein (GFP) gene, and infected it with each of four unrelated mycoviruses, including a partitivirus, a mycoreovirus, a megabirnavirus, and a quadrivirus. Infection with a mycoreovirus (R. necatrix mycoreovirus 3; RnMyRV3) suppressed RNA silencing of GFP, while the other mycoviruses did not. RnMyRV3 reduced accumulation of GFP-small interfering (si) RNAs and increased accumulation of GFP-double-stranded (ds) RNA; suggesting that the virus interferes with the dicing of dsRNA. Moreover, an agroinfiltration assay in planta revealed that the S10 gene of RnMyRV3 has RNA silencing suppressor activity. These data corroborate the counterdefense strategy of RnMyRV3 against host RNA silencing.
authors.affiliation: Apple Research Station, National Institute of Fruit Tree Science, National Agriculture and Food Research Organization (NARO), 92 Shimokuriyagawa, Morioka, Iwate 020-0123, Japan. hyae@affrc.go.jp
authors.forename: Hajime
authors.initials: H
authors.lastname: Yaegashi
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Yoshikawa
authors.forename: Tsutae
authors.initials: T
authors.lastname: Ito
authors.forename: Satoko
authors.initials: S
authors.lastname: Kanematsu
mesh_terms: D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D015967:Gene Expression Regulation, Viral; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000096:biosynthesis; D034622:RNA Interference; D012087:Reoviridae / Q000254:growth & development*; D013098:Xylariales / Q000235:genetics* / Q000821:virology*
chemical_list: D049452:Green Fluorescent Proteins
keywords: Mycovirus; RNA silencing; Reovirus; Rosellinia necatrix; Viral suppressor; dsRNA virus