Journal Article

Molecular characterization of four novel mycoviruses in entomopathogenic and nematophagous fungi

Zhou, Kang, Zhou, Rui, Tang, Zhimin, Wu, Shuang, Xu, Can, He, Yunhui, Zhang, Wen

2025

Overview

Background Research on fungal viruses has predominantly focused on phytopathogenic fungi, with some studies elucidating their roles in modulating fungal virulence and influencing plant-fungus interactions. In contrast, mycoviruses harbored by entomopathogenic and nematophagous fungi have received significantly less attention. Methods Eleven transcriptome datasets were de novo assembled and annotated using Diamond against the NCBI non-redundant protein database. Viral sequences, potential open reading frames (ORFs), and deduced amino acid sequences were analyzed using DNAMAN. Phylogenetic analysis was conducted based on the amino acid sequences. Results This study characterized four mycoviruses from Hirsutella satumaensis , Ophiocordyceps sinensis , and Orbilia oligospora . Based on BLASTp analysis, the amino acid sequences of these viral genomes showed 50% to 98% identity to those of known viruses. Detailed sequence analysis revealed that Hirsutella satumaensis botourmiavirus 1 (HsBV1), Ophiocordyceps sinensis mitovirus 4 (OsMV4), Orbilia oligospora negative-strand RNA virus 1 (OoNSV1), and Orbilia oligospora narnavirus 1 (OoNV1) contained nearly complete genomes. Each virus featured a single open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp) with a conserved GDD motif. Additionally, their variable 3′ untranslated regions (3′-UTRs) and 5′-UTRs were predicted to form stable stem-loop secondary structures, which may play roles in viral replication or stability. Phylogenetic analysis indicated that these mycoviruses belong to the families Aspiviridae , Botourmiaviridae , Mitoviridae , and Narnaviridae . Conclusions These findings expand our understanding of mycoviral diversity in nematophagous and entomopathogenic fungi. Further research is needed to explore whether these mycoviruses influence fungal interactions with insects or nematodes, which may uncover novel ecological and functional roles.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: 3' Untranslated regions / Amino Acid Sequence / Amino acids / Ascomycota - virology / Aspiviridae / Biomedical and Life Sciences / Biomedicine / Botourmiaviridae / data collection / Discovery and exploration / DNA-directed RNA polymerase / Entomopathogenic fungi / Fungal viruses / Fungal Viruses - classification / Fungal Viruses - genetics / Fungal Viruses - isolation & purification / Fungi / Fungi - virology / Genetic aspects / Genome, Viral / Genomes / Health aspects / Hirsutella / Identification and classification / mycoviruses / Narnaviridae / Nematoda / Nematodes / Nematophagous fungi / Open Reading Frames / Ophiocordyceps sinensis / Orbilia / Orbilia oligospora / Phylogenetics / Phylogeny / Physiological aspects / Phytopathogenic fungi / Plant diseases / Plant resistance / Proteins / RNA polymerase / RNA viruses / RNA, Viral - genetics / RNA-directed RNA polymerase / Sequence analysis / Taxonomy / transcriptome / Transcriptomes / Viral genetics / viral genome / Viral Proteins - genetics / Virology / Virulence / Virus diversity / virus replication / Virus research / Viruses