Planctomycetota

Abstract Planc.to.my.ce.to'ta. N.L. masc. n. Planctomyces , type genus of the phylum; L. neut. pl. n. suff. ‐ ota , ending to denote a phylum; N.L. neut. pl. n. Planctomycetota , the Planctomyces phylum. The phylum Planctomycetota (former name Planctomycetes ) was proposed in 2001 on the basis of the phylogenetic analysis of 16S rRNA gene sequences in order to accommodate several genera of budding aquatic bacteria. This is the only currently recognized phylum whose as‐yet‐uncultivated type genus, Planctomyces , was described based solely on its highly distinctive cell morphology. The current genome‐based classification suggests that the Planctomycetota accommodates 34 class‐level lineages, including two classes with validly published names, the Planctomycetia and Phycisphaerae , and two candidate classes, Candidatus Brocadiia and Candidatus Uabimicrobiia. Thirty additional as‐yet‐undescribed class‐level phylogenetic clades have digital identifiers. Only one of these clades, UBA1135, contains three cultivated representatives, while other clades are represented solely by metagenome‐assembled genomes (MAGs). The classes Planctomycetia and Phycisphaerae accommodate aerobic and anaerobic chemoorganotrophs, which utilize a wide range of organic compounds and divide by budding or by binary fission, respectively. Chemolithoautotrophic “anammox” planctomycetes, which are capable of anaerobic ammonium oxidation, comprise the class Candidatus Brocadiia. The class Candidatus Uabimicrobiia is represented only by two described members, which display amoeba‐like locomotion, phagocytosis‐like prey cell engulfment, and a unique mode of cell division. Functional roles of the Planctomycetota in the environment include decomposition of various biopolymers and participation in the global cycling of carbon and nitrogen. Members of this phylum are particularly abundant in aquatic habitats, but they also colonize various soils, peatlands, sediments, and other environments. Type genus : Planctomyces Gimesi 1924 AL .