A novel picorna-like virus, Riptortus pedestris virus-1 (RiPV-1), found in the bean bug, R. pedestris, after fungal infection

A viral genome was assembled de novo from next-generation sequencing (NGS) data from bean bugs, Riptortus pedestris, infected with an entomopathogenic fungus, Beauveria bassiana (Bb), and was further confirmed via the RACE method. This is a novel insect positive-sense single-stranded RNA virus, which we named Riptortus pedestris virus-1 (RiPV-1) (GenBank accession no. KU958718). The genome of RiPV-1 consists of 10,554 nucleotides (nt), excluding the poly(A) tail, which contains a single large open reading frame (ORF) of 10,371 nt encoding a polyprotein (3456 aa) and flanked by 71 and 112 nt at the 5′ and 3′ untranslated regions (UTR), respectively. RiPV-1 genome organization from the 5′ end contains a consensus organization of picorna-like RNA virus helicase, cysteine protease, and RNA-dependent RNA polymerase (RdRp), in addition to two putative structural proteins located at the 3′ region and a poly(A) tail at the 3′ end. The viral particles were approximately 30 nm in diameter with some dispersal distinctive surface projections. Based on the phylogenetic analysis of the RdRp sequences, RiPV-1 was clustered in the unassigned insect RNA viruses with two other viruses, APV and KFV. These three viruses were suggested to constitute a new group of insect RNA viruses. RiPV-1 could be found in all stages of lab-reared bean bugs and was detected abundantly in the thorax, abdomen, midgut and fat body, but not in the reproductive organs and muscle. Interestingly, RiPV-1 replication was increased dramatically in bean bugs 2–6 days after fungal infection. In conclusion, a novel insect RNA virus was found by NGS data assembly. This virus can provide further insight into the interaction between virus, fungus and the host.