Genome organization and molecular characterization of the three Formica exsecta viruses-FeV1, FeV2 and FeV4

Kishor Dhaygude; Helena Johansson; Jonna Kulmuni; Liselotte Sundström

doi:10.7717/peerj.6216

Genome organization and molecular characterization of the three Formica exsecta viruses-FeV1, FeV2 and FeV4

PeerJ. 2019 Feb 20:6:e6216. doi: 10.7717/peerj.6216. eCollection 2019.

Authors

Kishor Dhaygude¹, Helena Johansson¹, Jonna Kulmuni^{1

2}, Liselotte Sundström^{1

3}

Affiliations

¹ Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
² Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom.
³ Tvärminne Zoological Station, Faculty of Biological and Environmental Sciences, University of Helsinki, Hanko, Finland.

Abstract

We present the genome organization and molecular characterization of the three Formica exsecta viruses, along with ORF predictions, and functional annotation of genes. The Formica exsecta virus-4 (FeV4; GenBank ID: MF287670) is a newly discovered negative-sense single-stranded RNA virus representing the first identified member of order Mononegavirales in ants, whereas the Formica exsecta virus-1 (FeV1; GenBank ID: KF500001), and the Formica exsecta virus-2 (FeV2; GenBank ID: KF500002) are positive single-stranded RNA viruses initially identified (but not characterized) in our earlier study. The new virus FeV4 was found by re-analyzing data from a study published earlier. The Formica exsecta virus-4 genome is 9,866 bp in size, with an overall G + C content of 44.92%, and containing five predicted open reading frames (ORFs). Our bioinformatics analysis indicates that gaps are absent and the ORFs are complete, which based on our comparative genomics analysis suggests that the genomes are complete. Following the characterization, we validate virus infection for FeV1, FeV2 and FeV4 for the first time in field-collected worker ants. Some colonies were infected by multiple viruses, and the viruses were observed to infect all castes, and multiple life stages of workers and queens. Finally, highly similar viruses were expressed in adult workers and queens of six other Formica species: F. fusca, F. pressilabris, F. pratensis, F. aquilonia, F. truncorum and F. cinerea. This research indicates that viruses can be shared between ant species, but further studies on viral transmission are needed to understand viral infection pathways.

Keywords: Comparative analysis; Formica exsecta; Genome; Meta-transcriptome; Organization and characterization; RNA virus.

Grants and funding

The Academy of Finland (grants, #252411, #284666 to the Centre of Excellence in Biological Interactions), and the University of Helsinki provided funding, and the Doctoral programme LUOVA provided travel support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.