Termitidicoccus mucosus gen. nov. sp. nov. a novel Verrucomicrobiota species isolated from Reticulitermes chinensis gives insights of high adaptability of symbiotic bacteria to termite gut ecosystem

Verrucomicrobiota is widely distributed in various habitats including insect guts. It was found to be prevalent in almost all investigated termite guts, whereas their physiological functions are not very clear. In this study we characterized the physiological and genomic properties of Verrucomicrobiota strain TSB47^T isolated from Reticulitermes chinensis. The cells of strain TSB47^T were Gram-stain-negative, non-motile, and non-spore-forming coccoid with one or more warts. 16S rRNA gene analysis showed that the closest relatives of strain TSB47^T were Opitutaceae strain TAV1 and Ereboglobus luteus Ho45^T (98.3% and 95.4% sequence similarity, respectively). Whole genome analysis revealed that there are a large number of glycoside hydrolase genes, amino acid metabolism genes, complete Mo-Fe nitrogenase and Fe-Fe nitrogenase gene clusters, as well as cbb₃-type cytochrome oxidase gene in the genome of strain TSB47^T. Strain TSB47^T grows well under anaerobic and microaerophilic conditions with a strong tolerance to oxygen. Physiological and genomic characters of strain TSB47^T indicated its high adaptability to termite gut ecosystem. Based on phenotypic and phylogenetic evidence, we suggest strain TSB47^T as the type species of a novel genus in the family Opitutaceae, for which the name Termitidicoccus mucosus sp. nov. is proposed. The type strain is TSB47^T (CCTCC AB2022447^T; KCTC 102044^T).