Sustained RNA virome diversity in Antarctic penguins and their ticks

Abstract

Despite its isolation and extreme climate, Antarctica is home to diverse fauna and associated microorganisms. It has been proposed that the most iconic Antarctic animal, the penguin, experiences low pathogen pressure, accounting for their disease susceptibility in foreign environments. There is, however, a limited understanding of virome diversity in Antarctic species, the extent of in situ virus evolution, or how it relates to that in other geographic regions. To assess whether penguins have limited microbial diversity we determined the RNA viromes of three species of penguins and their ticks sampled on the Antarctic peninsula. Using total RNA sequencing we identified 107 viral species, comprising likely penguin associated viruses (n = 13), penguin diet and microbiome associated viruses (n = 82), and tick viruses (n = 8), two of which may have the potential to infect penguins. Notably, the level of virome diversity revealed in penguins is comparable to that seen in Australian waterbirds, including many of the same viral families. These data run counter to the idea that penguins are subject to lower pathogen pressure. The repeated detection of specific viruses in Antarctic penguins also suggests that rather than being simply spill-over hosts, these animals may act as key virus reservoirs.

Wild birds as reservoirs for diverse and abundant gamma- and deltacoronaviruses

“… 2018 ), although full genome sequences have also been generated in metatranscriptomic studies (Wille et al . 2018 , 2019 , 2020 ; Fig. 1 ).…”

“… 2018 ; Wille et al . 2019 , 2020 ). The amino acid similarity of these five viruses is 97–99% (ORF1ab; Fig 3 ), strongly suggesting they represent a single virus species under ICTV guidelines.…”

“…inhabiting the region, or the detection in a potential host reservoir species is to be determined (Wille et al . 2020 ).…”

Virome Temporal Variation During Sea Star Wasting Disease Progression in Pisaster ochraceus (Asteroidea, Echinodermata)

“…Picornaviruses (+ssRNA) feature prominently in most host-associated virome surveys [21][22][23][24][25][26][27][28][29][30][31][32] and are ubiquitous in marine plankton as free particles [33][34][35][36][37][38][39]. Of the 19 picornairus-like genome fragments recovered in this survey, 9 matched most closely to dicistroviruses (Dicistroviridae), 2 to bacillarnaviruses (Marnaviridae), and 1 to caliciviruses (Caliciviridae) by BLASTx (Fig.…”

Sequence diversity and evolution of an iflavirus family associated with ticks

“…Some iflaviruses have also been identified in ticks, for example in the tick Hyalomma asiaticum and in pools of different tick species [3]. Recently, a complete genome of an iflavirus has also been sequenced in an endemic Australian species, Ixodes holocyclus [9], in a tick species associated with marine birds, Ixodes uriae [10], and in the ISE6 cell line of Ixodes scapularis [11]. These findings illustrate two different strategies to isolate microorganisms, which each have their specific potential and interests: collecting and sequencing large pools of wild individuals (allowing to obtain sequences even for viruses that have a potentially low prevalence, as in [5] and [9]), or investigating well-characterized cell lines (as in [11]).…”