Tichowtungia aerotolerans gen. nov., sp. nov., a novel representative of the phylum Kiritimatiellaeota and proposal of Tichowtungiaceae fam. nov., Tichowtungiales ord. nov. and Tichowtungiia class. nov.
Da‐Shuai Mu, Liu-Yan Zhou, Qi‐Yun Liang, Guanjun Chen, Zong‐Jun Du
Abstract
Kiritimatiellaeota is widespread and ecologically important in various anoxic environments. However, the portion of culturable bacteria within this phylum is quite low and, in fact, there is only one currently described species. In this study, a novel anaerobic, non-motile, coccoid, Gram-stain-negative bacterial strain, designated S-5007 T , was isolated from surface marine sediment. The 16S rRNA gene sequence was found to have very low 16S rRNA gene sequence similarity to the nearest known type strain, Kiritimatiella glycovorans L21-Fru-AB T (84.9 %). The taxonomic position of the novel isolate was investigated using a polyphasic approach and comparative genomic analysis. Phylogenetic analyses based on 16S rRNA genes and genomes indicated that strain S-5007 T branched within the radiation of the phylum Kiritimatiellaeota . Different from the type strain, strain S-5007 T can grow under microaerobic conditions, and the genomes of strain S-5007 T and the other strains in its branch have many more antioxidant-related genes. Meanwhile, other different metabolic features deduced from genome analysis supported the separate evolution of the proposed class (strain S-5007 T branch) and K. glycovorans L21-Fru-AB T . Based on phylogenetic and phenotypic characterization studies, Tichowtungia aerotolerans gen. nov., sp. nov. is proposed with S-5007 T (=MCCC 1H00402 T =KCTC 15876 T ) as the type strain, as the first representative of novel taxa, Tichowtungiales ord. nov., Tichowtungiaceae fam. nov. in Tichowtungiia class. nov.