Conexivisphaera calida gen. nov., sp. nov., a thermophilic sulfur- and iron-reducing archaeon, and proposal of Conexivisphaeraceae fam. nov., Conexivisphaerales ord. nov., and Conexivisphaeria class. nov. in the phylum Thaumarchaeota
Shingo Kato, Masafumi Ohnishi, Mai Nagamori, Masahiro Yuki, Tomonori Takashina, Moriya Ohkuma, Takashi Itoh
Abstract
A thermoacidophilic, anaerobic, and iron- and sulfur-reducing archaeon, strain NAS-02 T , was isolated from a terrestrial hot spring in Japan, as previously reported. This organism is the first non-ammonia-oxidizing isolate in the phylum Thaumarchaeota . Here, we propose Conexivisphaera calida gen. nov., sp. nov. to accommodate this strain. The type strain of the type species is NAS-02 T (=JCM 31663 T =DSM 105898 T ). The values of 16S rRNA gene similarity and average amino acid identity between NAS-02 T and its closest relatives are <86 and <42 %, respectively. Based on the phylogeny and physiology, we propose the family Conexivisphaeraceae fam. nov., the order Conexivisphaerales ord. nov. and the class Conexivisphaeria class. nov. to accommodate the novel genus.