Alphaproteobacteria

Alphaproteobacteria
Transmission electron micrograph of Wolbachia within an insect cell. Credit:Public Library of Science / Scott O'Neill
Scientific classification
Domain:	Bacteria
Phylum:	Pseudomonadota
Class:	Alphaproteobacteria Garrity et al. 2006
Subclasses[1] and Orders[3]
Rickettsidae Ferla et al. 2013[1] Rickettsiales Gieszczykiewicz 1939 (Approved Lists 1980) "Pelagibacterales" Grote et al. 2012[2] Caulobacteridae Ferla et al. 2013[1] Caulobacterales Henrici and Johnson 1935 (Approved Lists 1980) Emcibacterales Iino et al. 2016 Holosporales Szokoli et al. 2020 Hyphomicrobiales Douglas 1957 (Approved Lists 1980) Iodidimonadales Iino et al. 2016 Kordiimonadales Kwon et al. 2005 Micropepsales Harbison et al. 2017 Parvularculales Garrity et al. 2003 Rhodobacterales Garrity et al. 2006 Rhodospirillales Pfennig and Trüper 1971 (Approved Lists 1980) Rhodothalassiales Venkata Ramana et al. 2014 Sneathiellales Kurahashi et al. 2008 Sphingomonadales Yabuuchi and Kosako 2006 "Taxa" incertae sedis (see text)
Synonyms[3]
Caulobacteria Cavalier-Smith 2020 Anoxyphotobacteria (Gibbons and Murray 1978) Murray 1988 Photobacteria Gibbons and Murray 1978 (Approved Lists 1980) Alphabacteria Cavalier-Smith 2002

Alphaproteobacteria or α-proteobacteria, also called α-Purple bacteria in earlier literature, is a class of bacteria in the phylum Pseudomonadota (formerly "Proteobacteria").^[4] The Magnetococcales and Mariprofundales are considered basal or sister to the Alphaproteobacteria.^[5][6] The Alphaproteobacteria are highly diverse and possess few commonalities, but nevertheless share a common ancestor. Like all Proteobacteria, its members are gram-negative, although some of its intracellular parasitic members lack peptidoglycan and are consequently gram variable.^[4][3]