A New Member of Melainabacteria, the Closest Relatives of Cyanobacteria
Melainabacteria are the recently discovered, closest non-photosynthetic relatives of cyanobacteria, the organisms responsible for the oxygenation of Earth\u27s atmosphere. Previous work has shown that Melainabacteria live in a wide range of environments, including deep groundwater, anoxic sediments, and the digestive tracts of termites and mammals. These bacteria have been suggested to play a significant role in the latter environments and may contribute to neurodegenerative and gastrointestinal disease in human populations. However, our knowledge of Melainabacteria diversity and metabolism is still very limited, principally because no member of this group has been successfully cultured in the laboratory.
Recently, DNA sequencing has revealed that a member of the Melainabacteria is growing in co-culture with an established diatom strain at the University of Montana’s Miller lab. In this study, we obtained a nearly complete Melainabacteria genome from metagenomic sequencing data. We then compared this genome to other previously sequenced Melainabacteria genomes to better understand genome architecture and the metabolic capacity of this bacterium. These data will guide further culturing efforts and future experiments. Together, our work will help clarify the functional role(s) of Melainabacteria in its environment and how it “makes a living” energetically. It will also provide new insights regarding the metabolic capabilities of the cyanobacterial ancestor and the origin of oxygenic photosynthesis
