Here, we report draft genome sequences for nine strains of “
Nanosynbacter sp. HMT-352.” These strains and their sequences were used to interrogate strain-level variations in host range, gene content, and growth dynamics among the phylum “
TM7 is one of the most enigmatic bacterial phyla among the uncultivated candidate phyla referred to as “microbial dark matter,” and it has potential pathogenic associations. We revealed molecular insights into its uncultivability and pathogenicity, as well its unique epibiotic and parasitic lifestyle phases. These novel discoveries shed significant light on the biological, ecological, and medical importance of TM7, as well as providing useful information for culturing other TM7 and currently uncultivable bacteria that may evade standard cultivation approaches.