Complete genome sequence of a novel iflavirus from wheat sawfly (Dolerus tritici)

Little is known about the insect viruses in wheat sawfly, Dolerus tritici, which is an important agricultural insect feeding on wheat leaves. Here, we used RNA sequencing to identify a novel single positive-strand RNA virus from the larvae of wheat sawfly collected in northern China and then determined its complete genome sequence by rapid amplification of cDNA ends. The complete genome is 9,594 nt in length, including a polyA tail at its 3′ terminus, and it is predicted to encode a 326.3-kDa polyprotein. Phylogenetic analysis based on deduced amino acid sequences of the polyprotein revealed that this RNA virus clustered in a clade with deformed wing virus of the genus Iflavirus, family Iflaviridae. The full genome of this RNA virus shows 42.0–50.0% sequence identity with other iflaviruses. Comparisons of amino acid sequences showed that the coat protein of this RNA virus is most similar to that of slow bee paralysis virus, with 33.6% identity, suggesting that this virus is a new member in the genus Iflavirus. Thus, we have tentatively designated it as “Dolerus tritici iflavirus 1” (DtIV1). To our knowledge, this is the first report of an insect virus in wheat sawfly.