uranium-oxidising autotrophs. The type order is the Acidithiobacillales, which includes economically important organisms used in the mining industry such as Acidithiobacillus spp. Taxonomy The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN) and the National Center for Biotechnology Information (NCBI). The group is defined primarily in terms of ribosomal RNA (rRNA) sequences. The Pseudomonadota are divided into several classes. These were previously regarded as subclasses of the phylum, but they are now treated as classes. These classes are monophyletic. The genus Acidithiobacillus, part of the Gammaproteobacteria until it was transferred to class Acidithiobacillia in 2013, was previously regarded as paraphyletic to the Betaproteobacteria according to multigenome alignment studies. In 2017, the Betaproteobacteria was subject to major revisions and the class Hydrogenophilalia was created to contain the order Hydrogenophilales Pseudomonadota classes with validly published names include some prominent genera: e.g.: Acidithiobacillia: Acidithiobacillus, Thermithiobacillus Alphaproteobacteria: Brucella, Rhizobium, Agrobacterium, Caulobacter, Rickettsia, Wolbachia, etc. Betaproteobacteria: Bordetella, Ralstonia, Neisseria, Nitrosomonas, etc. Gammaproteobacteria: Escherichia, Shigella, Salmonella, Yersinia, Buchnera, Haemophilus, Vibrio, Pseudomonas, etc. Zetaproteobacteria: Mariprofundus Transformation Transformation, a process in which genetic material passes from one bacterium to another, has been reported in at least 30 species of Pseudomonadota distributed in the classes alpha, beta, and gamma. The best-studied Pseudomonadota with respect to natural genetic transformation are the medically important human pathogens Neisseria gonorrhoeae (class beta), and Haemophilus influenzae (class gamma). Natural genetic transformation is a sexual process involving DNA transfer from one bacterial cell to another through the intervening medium and the integration of the donor sequence into the recipient genome. In pathogenic Pseudomonadota, transformation appears to serve as a DNA repair process that protects the pathogen's DNA from attack by their host's phagocytic defenses that employ oxidative free radicals. See also List of bacteria genera List of bacterial orders References External links Pseudomonadota information from Palaeos. Pseudomonadota. – J. P. Euzéby: List of Prokaryotic names with Standing in Nomenclature. Gram-negative bacteria Bacteria phyla