Metagenomic Insights into Nutrient-Related Genetic Potential of Antarctic Bryophyte-Associated Bacteria

Bryophytes are important components of Antarctic terrestrial vegetation and provide habitats for diverse bacterial taxa. These bacteria may contribute to nitrogen, phosphorus, and sulfur transformations, processes important for nutrient availability in Antarctic terrestrial ecosystems. However, information on the occurrence and taxonomic affiliation of genes involved in these transformations in bryophyte-associated bacteria remains limited. We analyzed bacterial taxonomic composition and selected nitrogen-, phosphorus-, and sulfur-related genes in metagenomes from nine bryophyte samples collected on Livingston Island, Antarctica. Bacterial taxonomic composition differed significantly among the nine bryophyte samples (R² = 0.770, p < 0.001), without significant differences in multivariate dispersion. Despite these differences, 1,309 of the 2,257 detected bacterial genera were shared by all nine samples. The occurrence of nitrogen-related genes differed among samples, while most targeted phosphorus-related genes and all targeted sulfur-related genes were detected across all nine metagenomes. Nutrient-related genes were associated with several bacterial phyla, including Pseudomonadota, Actinomycetota, and Cyanobacteriota. These results provide a baseline for further investigation of bacterial diversity and nutrient-related genetic potential in Antarctic bryophyte microbiomes.