The Characterization of Three Novel Insect-Specific Viruses Discovered in the Bean Bug, Riptortus pedestris

Abstract

Insect-specific virus (ISV) is one of the most promising agents for the biological control of insects, which is abundantly distributed in hematophagous insects. However, few ISVs have been reported in Riptortus pedestris (Fabricius), one of the major pests threatening soybeans and causing great losses in yield and quality. In this work, field Riptortus pedestris was collected from six soybean-producing regions in China, and their virome was analyzed with the metatranscriptomic approach. Altogether, seven new insect RNA viruses were identified, three of which had complete RNA-dependent RNA polymerase (RdRp) and nearly full-length genome sequences, which were named Riptortus pedestris alphadrosrha-like virus 1 (RpALv1), Riptortus pedestris alphadrosrha-like virus 2 (RpALv2) and Riptortus pedestris almendra-like virus (RiALv). The three identified novel ISVs belonged to the family Rhabdoviridae, and phylogenetic tree analysis indicated that they were clustered into new distinct clades. Interestingly, the analysis of virus-derived small-interfering RNAs (vsiRNAs) indicated that only RiALv-derived siRNAs exhibited 22 nt length preference, whereas no clear 21 or 22 nt peaks were observed for RpALv1 and RpALv2, suggesting the complexity of siRNA-based antiviral immunity in R. pedestris. In conclusion, this study contributes to a better understanding of the microenvironment in R. pedestris and provides viral information for the development of potential soybean insect-specific biocontrol agents.

Transcriptome Analysis Reveals a Diverse Range of Novel Viruses in Australian Sugarcane Soldier Fly (Inopus flavus) Larvae

“…These vsiRNAs are loaded into the RISC target RNA molecules through complementarity, reducing virus gene transcription and ultimately virus replication. This mechanism has previously been described for many insect RNAs [ 23 , 64 , 65 ] and DNA viruses [ 4 ]. For most insect viruses, the vsiRNAs display a sharp peak at 21 nt and are symmetrically distributed throughout the viral genome [ 28 , 66 ].…”

Diversity of RNA viruses in agricultural insects

“…Additionally, ISVs have been discovered in several stinkbug species, including a chuvirus in Nezara viridula [57] , a novel arlivirus in Erthesina fullo [58] , a picorna-like virus in Arma chinensis [90] , and seven new viral sequences from Halyomorpha halys [91] . In Riptortus pedestris , a bean bug that causes significant damage to leguminous plants, a total of five ISVs were identified [92] , [93] , [94] . Apart from the ISVs mentioned above, more ISVs have been found in several other hemipteran species related to agriculture.…”