Acidobacteriota

Abstract A.ci.do.bac.te.ri.o'ta. N.L. neut. n. Acidobacterium , type genus of the phylum; L. neut. pl. n. suff. ‐ ota , ending to denote a phylum; N.L. neut. pl. n. Acidobacteriota , the Acidobacterium phylum. The phylum Acidobacteriota (former name Acidobacteria ) was proposed in 1997 for the phylogenetic lineage defined by three cultivated representatives, Acidobacterium capsulatum , Geothrix fermentans , and Holophaga foetida . This lineage accommodated a large number of environmental 16S rRNA gene sequences, which were separated in 2007 into 26 major 16S rRNA gene sequence clades or subdivisions (SDs). In 2018, these SDs were assigned to 15 class‐level units, five of which contained taxonomically characterized members. The current genome‐based classification suggests that the Acidobacteriota accommodates 17 class‐level lineages, including five classes with validly published names, the Terriglobia , Blastocatellia , Vicinamibacteria , Thermoanaerobaculia , and Holophagae , and two candidate classes, Candidatus Aminicenantia and Candidatus Polarisedimenticolia. Ten additional as‐yet‐undescribed class‐level groups have digital identifiers and are represented solely by metagenome‐assembled genomes. Taxonomically characterized members of this phylum are Gram‐stain negative, non‐spore‐forming, aerobic, and anaerobic bacteria that display a wide variety of cell morphologies and differ with regard to pH and temperature preferences. Most characterized acidobacteria are chemoheterotrophs; photoheterotrophic members have so far been described only in the class Blastocatellia . Functional roles of the Acidobacteriota in the environment include decomposition of various biopolymers and participation in the global cycling of carbon, iron and hydrogen. These bacteria are particularly abundant in diverse soil habitats and wetlands, but they also colonize freshwater bodies and marine sediments.