Proteobacteria

Proteobacteria is the largest and most diverse phylum of Gram-negative bacteria, encompassing a broad range of ecological and medical significance. The group is subdivided into six classes: Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Epsilonproteobacteria, and Zetaproteobacteria. Members range from important human and animal pathogens (Escherichia coli, Salmonella, Neisseria, Helicobacter, Vibrio) and plant symbionts (Rhizobium) to environmental bacteria involved in nitrogen and sulfur cycling. The common feature across Proteobacteria is their Gram-negative cell envelope structure, but otherwise they display extensive metabolic and ecological diversity. The term was established based on 16S rRNA gene phylogeny.

Other names

Purple bacteriaProteobacterium