Complete nucleotide sequence of double-stranded RNA viruses from Fusarium graminearum strain DK3

Abstract

The complete genomes two different dsRNA mycoviruses, Fusarium graminearum virus 3 (FgV3) and Fusarium graminearum virus 4 (FgV4), was sequenced and analyzed. The viral genome of FgV3 is 9,098 base pairs (bp) long and contains two open reading frames (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp) and a protein of unknown function. The FgV4 genome is composed of two dsRNA genome segments of 2,383 bp and 1,739 bp. FgV4 dsRNA-1 contains a single ORF, which has a conserved RdRp motif, while FgV4 dsRNA-2 contains two putative ORFs coding for products of unknown function. Both the genome organization and phylogenetic analysis indicated that FgV3 was closely related to members of the families Totiviriridae and Chrysoviridae, but it was placed outside of their main clusters, whereas FgV4 formed a distinct clade with the family Partitiviridae. This is the first report of the full-length nucleotide sequences of FgV3 and FgV4 infecting Fusarium graminearum.