Background: Bathyarchaeota, a newly proposed archaeal phylum, is considered as an important driver of the global carbon cycle. However, due to the great diversity of them, there is limited genomic information that accurately encompasses the metabolic potential of the entire archaeal phylum.
Results: In the current study, nine metagenome-assembled genomes of Bathyarchaeota from four subgroups were constructed from mangrove sediments, and metatranscriptomes were obtained for evaluating their in situ transcriptional activities. Comparative analyses with reference genomes and the transcripts of functional genes posit an expanded role for Bathyarchaeota in phototrophy, autotrophy, and nitrogen and sulfur cycles, respectively. Notably, the presence of genes for rhodopsins, cobalamin biosynthesis, and the oxygen-dependent metabolic pathways in some Bathyarchaeota subgroup 6 genomes suggest a light-sensing and microoxic lifestyle within this subgroup.
Conclusions: The results of this study expand our knowledge of metabolic abilities and diverse lifestyles of Bathyarchaeota, highlighting the crucial role of Bathyarchaeota in geochemical cycle. Video abstract.
Keywords: Bathyarchaeota; Calvin-Benson-Bassham cycle; Microoxic lifestyle; Porphyrin biosynthesis; Rhodopsin; Trimethylamine degradation; Urea producing.