title: Genome rearrangement of a mycovirus Rosellinia necatrix megabirnavirus 1 affecting its ability to attenuate virulence of the host fungus.
abstract: Rosellinia necatrix megabirnavirus 1 (RnMBV1) is a bi-segmented double-stranded RNA mycovirus that reduces the virulence of the fungal plant pathogen R. necatrix. We isolated strains of RnMBV1 with genome rearrangements (RnMBV1-RS1) that retained dsRNA1, encoding capsid protein (ORF1) and RNA-dependent RNA polymerase (ORF2), and had a newly emerged segment named dsRNAS1, but with loss of dsRNA2, which contains two ORFs of unknown function. Analyses of two variants of dsRNAS1 revealed that they both originated from dsRNA1 by deletion of ORF1 and partial tandem duplication of ORF2, retaining a much shorter 5' untranslated region (UTR). R. necatrix transfected with RnMBV-RS1 virions showed maintenance of virulence on host plants compared with infection with RnMBV1. This suggests that dsRNAS1 is able to be transcribed and packaged, as well as suggesting that dsRNA2, while dispensable for virus replication, is required to reduce the virulence of R. necatrix.
authors: NARO, Institute of Fruit Tree Science, Shimokuriyagawa, Morioka 020-0123, Japan. Electronic address: satokok@affrc.go.jp.
authors: Satoko
authors: S
authors: Kanematsu
authors: NARO, Institute of Fruit Tree Science, Shimokuriyagawa, Morioka 020-0123, Japan.
authors: Takeo
authors: T
authors: Shimizu
authors: Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan.
authors: Lakha
authors: L
authors: Salaipeth
authors: NARO, Institute of Fruit Tree Science, Shimokuriyagawa, Morioka 020-0123, Japan.
authors: Hajime
authors: H
authors: Yaegashi
authors: NARO, Institute of Fruit Tree Science, 2-1 Fujimoto, Tsukuba 305-8605, Japan.
authors: Atsuko
authors: A
authors: Sasaki
authors: NARO, Institute of Fruit Tree Science, Shimokuriyagawa, Morioka 020-0123, Japan.
authors: Tsutae
authors: T
authors: Ito
authors: Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan.
authors: Nobuhiro
authors: N
authors: Suzuki
mesh_terms: D016679:Genome, Viral; D027845:Malus / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D012328:RNA Viruses / Q000145:classification / Q000235:genetics* / Q000502:physiology; D011995:Recombination, Genetic; D014774:Virulence; D014779:Virus Replication; D013098:Xylariales / Q000472:pathogenicity* / Q000502:physiology / Q000821:virology*
keywords: Fungal virus; Genomic rearrangement; Virulence