The phylum gemmatimonadetes

Abstract

The phylum Gemmatimonadetes was proposed based on the sole isolate, Gemmatimonas aurantiaca, in 2003. Although the phylum has still contained only one valid genus and species to date (December, 2012), it consists an enormous number of environmental 16S rRNA gene sequences retrieved from soil and marine environments. The phylogenetic divergence of constituent sequences in this phylum is as large as those in the phyla Actinobacteria and Proteobacteria. The type strain of G. Aurantiaca, strain T-27T, was isolated from activated sludge in a wastewater treatment system operated under enhanced biological phosphorus removal (EBPR) conditions. Cells are positively Neisser stained and show strong yellow fluorescence with 4,6-diamidino-2-phenylindole (DAPI), suggesting intracellular accumulation of a significant amount of storage materials such as polyphosphate. The liquid culture and colonies of G. Aurantiaca are orange to pink due to the possession of rare carotenoids, oscillol 2,2′-diglycosides and deoxyoscillol 2-rhamnoside. The latter is a new carotenoid first discovered in G. Aurantiaca.