Acidobacteriota is a phylum of Gram-negative bacteria. Its members are physiologically diverse and ubiquitous, especially in soils, but are under-represented in culture.

Description

Members of this phylum are physiologically diverse, and can be found in a variety of environments including soil, decomposing wood, hot springs, oceans, caves, and metal-contaminated soils. The members of this phylum are particularly abundant in soil habitats representing up to 52% of the total bacterial community. Environmental factors such as pH and nutrients have been seen to drive Acidobacteriota dynamics. Many Acidobacteriota are acidophilic, including the first described member of the phylum, Acidobacterium capsulatum.

There is much that is unknown about Acidobacteria both in their form and function. Thus, this is a growing field of microbiology. Some of this uncertainty can be attributed to the difficulty with which these bacteria are grown in the laboratory. There has been recent success in propagation by using low concentrations of nutrients in combination with high amounts of CO<sub>2</sub>, Geothrix fermentans, Acanthopleuribacter pedis and Bryobacter aggregatus.

Since they have only recently been discovered and the large majority have not been cultured, the ecology and metabolism of these bacteria is not well understood. Members of subdivisions 1, 4, and 6 are found to be particularly abundant in soils.

As well as their natural soil habitat, unclassified subdivision 2 Acidobacteriota have also been identified as a contaminant of DNA extraction kit reagents, which may lead to their erroneous appearance in microbiota or metagenomic datasets.

Members of subdivision 1 have been found to dominate in low pH conditions. potentially due to cell specialization and enzyme stability. There are some Acidobacteriota that are considered anaerobes within subdivision 8 It has been found that some strains of Acidobacteriota originating from soils have the genomic potential to respire oxygen at atmospheric and sub-atmospheric concentrations. However, Acidobacteriota were not recognized as a distinct clade until 1997,

Subdivisions

In an effort to further classify Acidobacteria, 16S rRNA gene regions were sequenced from many different strains. These sequences lead to the formation of subdivisions within the phyla. Today, there are 26 accepted subdivisions recognized in the Ribosomal Database Project. Members of subdivision 1 also contain enzymes such as galactosidases used in the breakdown of sugars. and National Center for Biotechnology Information (NCBI).

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! colspan=1 | 16S rRNA based phylogeny

! colspan=1 | 16S rRNA based LTP_10_2024

! colspan=1 | 120 marker proteins based GTDB 10-RS226

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See also

  • List of bacterial orders
  • List of bacteria genera

References

  • Acidobacteria bacterium Ellin345 Genome Page
  • Acidobacterium Genome Projects (from Genomes OnLine Database)
  • Science Daily article
  • Scientific American article
  • acidoseq, A Python package for studying Acidobacteria