Horizontal transfer of a non-autonomous Helitron among insect and viral genomes

Authors: Coates, Brad

Submitted to: BMC Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2015
Publication Date: 2/27/2015
Citation: Coates, B.S. 2015. Horizontal transfer of a non-autonomous Helitron among insect and viral genomes. Biomed Central (BMC) Genomics. 16(1):137.

Interpretive Summary: Interactions of plants and plant-feeding insects have resulted in a co-evolution between these organisms. Short segments of DNA in insects, plant infecting viruses, and plant genomes were shown to be highly similar, and these predicted DNA segments belong to class DNA elements that are known to be mobile within and between genomes. These data analyzed by an ARS Scientist showed that mobile DNA can be transferred between plants and plant feeding insects, and have broad implications in understanding plant insect interactions. These data are of interest to public and private scientists and government regulators.

Technical Abstract: The movement of genetic material among species by horizontal transfer (HT) influences genome evolution through the modification of structure and function. Helitrons are a relatively new lineage of DNA-based (class II) transposable elements (TEs) that propagate by rolling-circle replication and are capable of acquiring host DNA. Rapid spread of Helitrons among lineages by HT occurs by shuttling in viral particles or by unknown mechanisms mediated by host parasite associations. However, the role and impact that HT plays on genome evolution remains largely unknown. Here we show that HT is likely responsible for movement a non-autonomous Helitron, Hel-2, among insects, virus, and plant genomes. Hel-2 was found to share high sequence conservation and a discontinuous distribution among insects from the Order Lepidoptera. Bioinformatic predictions detected Hel-2 in the genomes of insects and insect viruses. Furthermore, Hel-2 Helitrons were discovered in the genomes plant species; melon, Cucumis melo, potato, and wild rice, Oryza spp. These results provide seminal evidence that TEs might have moved between herbivorous insects and their host plants by HT. This genetic exchange across distant genera provides new perspectives on the scope of genetic exchange across preconceived evolutionary boundaries.