Verrucomicrobiota is a phylum of Gram-negative bacteria that contains only a few described species. The species identified have been isolated from fresh water, marine and soil environments and human faeces. A number of as-yet uncultivated species have been identified in association with eukaryotic hosts including extrusive explosive ectosymbionts of protists and endosymbionts of nematodes from genus Xiphinema, residing in their gametes. The verrucomicrobial bacterium Akkermansia muciniphila is a human intestinal symbiotic bacterium that is considered as a promising probiotic. Verrucomicrobiota are abundant within the environment, though relatively inactive. This phylum is considered to have two sister phyla: Chlamydiota (formerly Chlamydiae) and Lentisphaerota (formerly Lentisphaerae) within the PVC superphylum. The Verrucomicrobiota phylum can be distinguished from neighbouring phyla within the PVC group by the presence of several conserved signature indels (CSIs). These CSIs represent unique, synapomorphic characteristics that suggest common ancestry within Verrucomicrobiota and an independent lineage amidst other bacteria. CSIs have also been found that are shared by Verrucomicrobiota and Chlamydiota exclusively of all other bacteria. These CSIs provide evidence that Chlamydiota is the closest relative to Verrucomicrobiota, and that they are more closely related to one another than to the Planctomycetales. Verrucomicrobiota might belong in the clade Planctobacteria in the larger clade Gracilicutes. In 2008, the whole genome of Methylacidiphilum infernorum (2.3 Mbp) was published. On the single circular chromosome, 2473 predicted proteins were found, 731 of which had no detectable homologs. These analyses also revealed many possible homologies with Pseudomonadota.

Phylogeny

Taxonomy

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI)