Molecular characterization of a novel endornavirus isolated from Ophiostoma bicolor associated with bark beetles

Abstract

Ophiostoma bicolor is a pathogen fungus associated with bark beetles that can cause serious damage to host plants. In this study, a novel fungal virus "Ophiostoma bicolor endornavirus 1" (ObEV1) was obtained from O. bicolor, and its complete genome sequence was determined. ObEV1 has a singlestranded positive-sense (+ss) RNA genome of 10119 nucleotides, Sequence annotation and comparison showed that the viral genome has a single large open reading frame (ORF) encoding a polyprotein of 362.48 kDa. The polyprotein contains seven conserved domains: RNA dependent RNA polymerase (RdRp), Viral RNA Helicase 1 (VHel1), Viral-methyltransferase (VMet), DEAD-like helicases (DEXDc), gliding-GltJ (G1), large tegument protein UL36 (PHA) and YlqF-related-GTPase (Y). Sequence comparisons and phylogenetic analysis showed that ObEV1 is a novel mycovirus belonging to the Betaendornavirus of "Endornaviridae" family. This is the first report of mycovirus in O. bicolor of Ophiostomatoid fungi.