Novel Dicistroviruses in an Unexpected Wide Range of Invertebrates

Dicistroviruses are members of a rapidly growing family of small RNA viruses. Related sequences have been discovered in many environmental samples, indicating that our knowledge about dicistrovirus diversity and host range is still limited. In this study, we performed a systematic search against the publicly available transcriptome database, and identified large numbers of dicistrovirus-like sequences in a wide variety of eukaryotic species. The origins of these sequences were 108 invertebrates (including 77 insect species belonging to 18 orders) and 11 plants, revealing new associations between dicistroviruses and hosts. Finally, 83 transcripts corresponding to nearly-complete viral genomes were retrieved from the RNA-seq data, of which most sequences showed limited similarity to known dicistroviruses and might present previously unreported virus species. Phylogenetic analysis suggested that horizontal virus transfer has occurred between diverse hosts and has important implications for dicistrovirus evolution. The results will provide new insight into the hidden diversity of the Dicistroviridae, and help us to better understand the viral evolution, host range and the possible way of transmission.