Arboribacterium acericorticis gen. nov., sp. nov., an under-represented oligotrophic bacterium of the phylum Abditibacteriota isolated from the bark of Acer palmatum

Only a small fraction of environmental micro-organisms has been isolated and cultivated, and deepening our understanding of under-represented taxa is important for unveiling unknown microbial ecosystems and accumulating bioresources. To date, only one strain of the phylum Abditibacteriota has been isolated and remains poorly characterized. We isolated strain IAD-21T, a member of the phylum Abditibacteriota, from the bark of Acer palmatum, and its characteristics are described in this report. Strain IAD-21T is a Gram-negative, oligotrophic, slow-growing, aerobic heterotrophic bacterium, and its cells are tetrad or sarcina cocci. The growth temperature and pH range from 15 to 37 °C and 6.0 to 7.4, respectively, and the strain forms pink colonies on agar medium. The 16S rRNA gene sequence similarity between this strain and Abditibacterium utsteinense strain LMG 29911T was 90.83%, and the average amino acid identity and percentage of conserved proteins values were 63.93% and 48.80%, respectively. Phylogenetic analysis based on the 16S rRNA gene and genome sequences revealed that strains IAD-21T and LMG 29911T were placed in separate clusters. The genome size of strain IAD-21T was 7.4 Mb, and it contained a 102 kb plasmid. The G+C content of the genomic DNA was 55.05 mol%. The genome sequence of strain IAD-21T contains genes encoding various carbohydrate-active enzymes, suggesting that this strain is involved in the degradation of plant cell wall components. Based on the phylogenetic and physiological analyses, we propose the name Arboribacterium acericorticis gen. nov., sp. nov. (type strain IAD-21T=JCM 32665T=DSM 108248T), which belongs to the family Abditibacteriaceae.