title: Comparative genomic analysis of magnetotactic bacteria from the Deltaproteobacteria provides new insights into magnetite and greigite magnetosome genes required for magnetotaxis.
abstract: Magnetotactic bacteria (MTB) represent a group of diverse motile prokaryotes that biomineralize magnetosomes, the organelles responsible for magnetotaxis. Magnetosomes consist of intracellular, membrane-bounded, tens-of-nanometre-sized crystals of the magnetic minerals magnetite (Fe3O4) or greigite (Fe3S4) and are usually organized as a chain within the cell acting like a compass needle. Most information regarding the biomineralization processes involved in magnetosome formation comes from studies involving Alphaproteobacteria species which biomineralize cuboctahedral and elongated prismatic crystals of magnetite. Many magnetosome genes, the mam genes, identified in these organisms are conserved in all known MTB. Here we present a comparative genomic analysis of magnetotactic Deltaproteobacteria that synthesize bullet-shaped crystals of magnetite and/or greigite. We show that in addition to mam genes, there is a conserved set of genes, designated mad genes, specific to the magnetotactic Deltaproteobacteria, some also being present in Candidatus Magnetobacterium bavaricum of the Nitrospirae phylum, but absent in the magnetotactic Alphaproteobacteria. Our results suggest that the number of genes associated with magnetotaxis in magnetotactic Deltaproteobacteria is larger than previously thought. We also demonstrate that the minimum set of mam genes necessary for magnetosome formation in Magnetospirillum is also conserved in magnetite-producing, magnetotactic Deltaproteobacteria. Some putative novel functions of mad genes are discussed.
authors.affiliation: CEA Cadarache/CNRS/Aix-Marseille Université, UMR7265 Service de Biologie Végétale et de Microbiologie Environnementale, Laboratoire de Bioénergétique Cellulaire, 13108, Saint Paul lez Durance, France.
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Lefèvre
authors.forename: Denis
authors.initials: D
authors.lastname: Trubitsyn
authors.forename: Fernanda
authors.initials: F
authors.lastname: Abreu
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kolinko
authors.forename: Christian
authors.initials: C
authors.lastname: Jogler
authors.forename: Luiz Gonzaga Paula
authors.initials: LG
authors.lastname: de Almeida
authors.forename: Ana Tereza R
authors.initials: AT
authors.lastname: de Vasconcelos
authors.forename: Michael
authors.initials: M
authors.lastname: Kube
authors.forename: Richard
authors.initials: R
authors.lastname: Reinhardt
authors.forename: Ulysses
authors.initials: U
authors.lastname: Lins
authors.forename: David
authors.initials: D
authors.lastname: Pignol
authors.forename: Dirk
authors.initials: D
authors.lastname: Schüler
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Bazylinski
authors.forename: Nicolas
authors.initials: N
authors.lastname: Ginet
mesh_terms: D017124:Conserved Sequence; D020564:Deltaproteobacteria / Q000145:classification / Q000235:genetics*; D052203:Ferrosoferric Oxide; D016680:Genome, Bacterial / Q000235:genetics*; D007501:Iron; D008280:Magnetics; D055944:Magnetosomes / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D010802:Phylogeny; D013440:Sulfides
chemical_list: D013440:Sulfides; C111959:greigite; D007501:Iron; D052203:Ferrosoferric Oxide