Journal Article

Description of a Novel Mycovirus in the Phytopathogen Fusarium culmorum and a Related EVE in the Yeast Lipomyces starkeyi

Liénard, Charlotte, Mahillon, Mathieu, Legrève, Anne, Bragard, Claude, Romay, Gustavo

2020

Overview

A new mycovirus was found in the Fusarium culmorum strain A104-1 originally sampled on wheat in Belgium. This novel virus, for which the name Fusarium culmorum virus 1 (FcV1) is suggested, is phylogenetically related to members of the previously proposed family ‘’Unirnaviridae’’. FcV1 has a monopartite dsRNA genome of 2898 bp that harbors two large non-overlapping ORFs. A typical -1 slippery motif is found at the end of ORF1, advocating that ORF2 is translated by programmed ribosomal frameshifting. While ORF2 exhibits a conserved replicase domain, ORF1 encodes for an undetermined protein. Interestingly, a hypothetically transcribed gene similar to unirnaviruses ORF1 was found in the genome of Lipomyces starkeyi, presumably resulting from a viral endogenization in this yeast. Conidial isolation and chemical treatment were unsuccessful to obtain a virus-free isogenic line of the fungal host, highlighting a high retention rate for FcV1 but hindering its biological characterization. In parallel, attempt to horizontally transfer FcV1 to another strain of F. culmorum by dual culture failed. Eventually, a screening of other strains of the same fungal species suggests the presence of FcV1 in two other strains from Europe.

• Publisher: MDPI AG,MDPI
• Subject: Amino Acid Sequence / Belgium / chemical treatment / Communication / conidia / double-stranded RNA / dsRNA / enzymes / EVE / Fungal Viruses - classification / Fungal Viruses - genetics / Fungal Viruses - isolation & purification / Fusarium - virology / Fusarium culmorum / genes / Genetic aspects / Genome, Viral / Lipomyces - virology / Lipomyces starkeyi / mycovirus / mycoviruses / open reading frames / Phylogeny / Physiological aspects / Plant Diseases - microbiology / plant pathogens / RNA-Dependent RNA Polymerase - chemistry / RNA-Dependent RNA Polymerase - genetics / screening / Sequence Alignment / transcription (genetics) / Unirnaviridae / Viral Proteins - chemistry / Viral Proteins - genetics / Viruses / wheat / yeasts / Yeasts (Fungi)