Identification of shared viral sequences in peat moss metagenomes reveals elements of a possible Sphagnum core virome.

BACKGROUND

Viruses are an understudied component of plant microbiomes. Identifying viruses that are shared between individual plants, or members of the “core virome”, could reveal stable viral populations with the potential to modulate the composition and function of the microbiome. Here, we examined the virome associated with mosses, a keystone species that has direct influence over the fate of peatland carbon stores. We analyzed bulk metagenomes and metatranscriptomes generated from field samples collected over a ten-month period to identify virus-like sequences shared among plants.

RESULTS

Individual samples harbored distinct DNA and RNA viromes where only a small percentage (< 1%) of the total number of identified viral contigs were shared among all samples. Based on taxonomic classification, the shared viral contigs represent bacterial viruses, or phage (), as well as viruses of eukaryotes, namely nucleocytoplasmic large DNA viruses () and RNA viruses (). We linked the shared phage-like contigs to viral regions within sequenced genomes of bacterial taxa that are members of the core microbiome, suggesting that these contigs represent temperate phage or degraded prophage. The putative nucleocytoplasmic large DNA viruses and RNA viruses were phylogenetically diverse and showed sequence similarity to viruses associated with a broad range of hosts and environmental sources.

CONCLUSIONS

The identification of shared viral contigs suggested that, despite the compositional heterogeneity between samples, mosses may harbor a core virome. Future work validating the presence of the core virome is warranted as it may aid in understanding how persistent viruses impact microbiome ecology and symbiont evolution within this climatically relevant keystone species.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s40793-025-00719-0.