Circumpolar diversification of the Ixodes uriae tick virome

• Published in: PLOS Pathogens
• Main Authors: Pettersson, John H.-O., Ellström, Patrik, Ling, Jiaxin, Nilsson, Ingela, Bergström, Sven, Gonzalez-Acuna, Daniel, Olsen, Björn, Holmes, Edward C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Umeå universitet, Institutionen för molekylärbiologi (Medicinska fakulteten) 2020
• Subjects: Microbiology; Mikrobiologi; Bonden; Neko; Neko Harbour; Okhotskiy; Alca torda; Antarc*; Antarctica; Common Murre; Gentoo penguin; Northern Sweden; Pygoscelis papua; Razorbill; Uria aalge; uria
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-174946; https://doi.org/10.1371/journal.ppat.1008759

Ticks (order: Ixodida) are a highly diverse and ecologically important group of ectoparasitic blood-feeding organisms. One such species, the seabird tick (Ixodes uriae), is widely distributed around the circumpolar regions of the northern and southern hemispheres. It has been suggested thatIx.uriaespread from the southern to the northern circumpolar region millions of years ago and has remained isolated in these regions ever since. Such a profound biographic subdivision provides a unique opportunity to determine whether viruses associated with ticks exhibit the same evolutionary patterns as their hosts. To test this, we collectedIx.uriaespecimens near a Gentoo penguin (Pygoscelis papua) colony at Neko harbour, Antarctica, and from migratory birds-the Razorbill (Alca torda) and the Common murre (Uria aalge)-on Bonden island, northern Sweden. Through meta-transcriptomic next-generation sequencing we identified 16 RNA viruses, seven of which were novel. Notably, we detected the same species, Ronne virus, and two closely related species, Bonden virus and Piguzov virus, in both hemispheres indicating that there have been at least two cross-circumpolar dispersal events. Similarly, we identified viruses discovered previously in other locations several decades ago, including Gadgets Gully virus, Taggert virus and Okhotskiy virus. By identifying the same or closely related viruses in geographically disjunct sampling locations we provide evidence for virus dispersal within and between the circumpolar regions. In marked contrast, our phylogenetic analysis revealed no movement of theIx.uriaetick hosts between the same locations. Combined, these data suggest that migratory birds are responsible for the movement of viruses at both local and global scales. Author summary: As host populations diverge, so may those microorganisms, including viruses, that are dependent on those hosts. To examine this key issue in host-microbe evolution we compared the co-phylogenies of the seabird tick,Ixodes uriae, and their RNA viruses sampled ...