2025/02/10 by Meri Nakajima, Ryosuke Nakai, Yuga Hirakata +5 · 1 voice · 1 citation
Biochemistry, Genetics and Molecular Biology · Environmental Science · #Genomics and Phylogenetic Studies #Gut microbiota and health #Microbial Community Ecology and Physiology
paper · doi:10.1099/ijsem.0.006668
openalex publication_date 2025/02/10 · openalex created_date 2025/02/11 · openalex updated_date 2026/07/30
In the domain Bacteria , one of the largest, most diverse and environmentally ubiquitous phylogenetic groups, Candidatus Patescibacteria (also known as candidate phyla radiation/CPR), remains poorly characterized, leaving a major knowledge gap in microbial ecology. We recently discovered a novel cross-domain symbiosis between Ca . Patescibacteria and Archaea in highly purified enrichment cultures and proposed Candidatus taxa for the characterized species, including Ca . Minisyncoccus archaeophilus and the corresponding family Ca . Minisyncoccaceae. In this study, we report the isolation of this bacterium, designated strain PMX.108 T , in a two-strain co-culture with a host archaeon, Methanospirillum hungatei strain DSM 864 T (JF-1 T ), and hereby describe it as the first representative species of Ca . Patescibacteria. Strain PMX.108 T was isolated from mesophilic methanogenic sludge in an anaerobic laboratory-scale bioreactor treating synthetic purified terephthalate- and dimethyl terephthalate-manufacturing wastewater. The strain could not grow axenically and is obligately anaerobic and parasitic, strictly depending on M. hungatei as a host. The genome was comparatively large (1.54 Mbp) compared to other members of the clade, lacked some genes involved in the biosynthesis pathway and encoded type IV pili-related genes associated with the parasitic lifestyle of ultrasmall microbes. The G+C content of the genomic DNA was 36.6 mol%. Here, we report the phenotypic and genomic properties of strain PMX.108 T ; we propose Minisyncoccus archaeiphilus gen. nov., sp. nov. to accommodate this strain. The type strain of the species is PMX.108 T (=JCM 39522 T ). We also propose the associated family, order, class and phylum as Minisyncoccaceae fam. nov. Minisyncoccales nov., Minisyncoccia class. nov. and Minisyncoccota phyl. nov. within the bacterial kingdom Bacillati .