PNNL

Abstract

Permafrost in the Arctic is thawing due to global warming, with unknown consequences on microbial interactions and ecological processes, including the role of viruses in regulating host dynamics. Although DNA viruses have previously been shown to be abundant and active in thawing permafrost, little is known about RNA viruses or their hosts. It is necessary to fill this knowledge gap as many RNA viruses are potential human, animal and plant pathogens. Here, we assessed the composition of RNA viruses in thawed permafrost samples that were incubated for 97 days at 4°C to simulate thaw conditions. A diverse RNA viral community was assembled from metatranscriptome data including double-stranded RNA viruses, dominated by Reoviridae and Hypoviridae, and negative and positive single stranded RNA viruses, with relatively high representations of Rhabdoviridae and Leviviridae, respectively. Importantly, potential plant and human pathogens were also detected, such as Tospoviridae and Rhabdoviridae. The permafrost RNA viruses primarily targeted the dominant active Eukarya in the samples (e.g., fungi, Metazoa and Viridiplantae) and their compositions were significantly associated with predicted host populations. These results indicate that RNA viruses directly respond to eukaryotic host dynamics. In addition, several permafrost RNA viral sequences contained genes encoding proteins involved in carbon utilization (e.g., polygalacturonase), implying their potential contribution to carbon cycling in permafrost.