title: Comparative genomic analysis provides insights into the evolution and niche adaptation of marine Magnetospira sp. QH-2 strain.
abstract: Magnetotactic bacteria (MTB) are capable of synthesizing intracellular organelles, the magnetosomes, that are membrane-bounded magnetite or greigite crystals arranged in chains. Although MTB are widely spread in various ecosystems, few axenic cultures are available, and only freshwater Magnetospirillum spp. have been genetically analysed. Here, we present the complete genome sequence of a marine magnetotactic spirillum, Magnetospira sp. QH-2. The high number of repeats and transposable elements account for the differences in QH-2 genome structure compared with other relatives. Gene cluster synteny and gene correlation analyses indicate that the insertion of the magnetosome island in the QH-2 genome occurred after divergence between freshwater and marine magnetospirilla. The presence of a sodium-quinone reductase, sodium transporters and other functional genes are evidence of the adaptive evolution of Magnetospira sp. QH-2 to the marine ecosystem. Genes well conserved among freshwater magnetospirilla for nitrogen fixation and assimilatory nitrate respiration are absent from the QH-2 genome. Unlike freshwater Magnetospirillum spp., marine Magnetospira sp. QH-2 neither has TonB and TonB-dependent receptors nor does it grow on trace amounts of iron. Taken together, our results show a distinct, adaptive evolution of Magnetospira sp. QH-2 to marine sediments in comparison with its closely related freshwater counterparts.
authors.affiliation: Laboratoire de Chimie Bactérienne, Aix-Marseille Université, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7283, F-13402, Marseille Cedex 20, France.
authors.forename: Boyang
authors.initials: B
authors.lastname: Ji
authors.forename: Sheng-Da
authors.initials: SD
authors.lastname: Zhang
authors.forename: Pascal
authors.initials: P
authors.lastname: Arnoux
authors.forename: Zoe
authors.initials: Z
authors.lastname: Rouy
authors.forename: François
authors.initials: F
authors.lastname: Alberto
authors.forename: Nadège
authors.initials: N
authors.lastname: Philippe
authors.forename: Dorothée
authors.initials: D
authors.lastname: Murat
authors.forename: Wei-Jia
authors.initials: WJ
authors.lastname: Zhang
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Rioux
authors.forename: Nicolas
authors.initials: N
authors.lastname: Ginet
authors.forename: Monique
authors.initials: M
authors.lastname: Sabaty
authors.forename: Sophie
authors.initials: S
authors.lastname: Mangenot
authors.forename: Nathalie
authors.initials: N
authors.lastname: Pradel
authors.forename: Jiesheng
authors.initials: J
authors.lastname: Tian
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Lichen
authors.initials: L
authors.lastname: Zhang
authors.forename: Wenyan
authors.initials: W
authors.lastname: Zhang
authors.forename: Hongmiao
authors.initials: H
authors.lastname: Pan
authors.forename: Bernard
authors.initials: B
authors.lastname: Henrissat
authors.forename: Pedro M
authors.initials: PM
authors.lastname: Coutinho
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Tian
authors.initials: T
authors.lastname: Xiao
authors.forename: Claudine
authors.initials: C
authors.lastname: Médigue
authors.forename: Valérie
authors.initials: V
authors.lastname: Barbe
authors.forename: David
authors.initials: D
authors.lastname: Pignol
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Talla
authors.forename: Long-Fei
authors.initials: LF
authors.lastname: Wu
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D005075:Biological Evolution; D055028:Comparative Genomic Hybridization; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics; D017753:Ecosystem; D016680:Genome, Bacterial; D044404:Genomic Islands; D055944:Magnetosomes / Q000235:genetics; D042201:Magnetospirillum / Q000235:genetics* / Q000502:physiology; D005810:Multigene Family; D010802:Phylogeny; D011808:Quinone Reductases / Q000235:genetics; D012623:Seawater / Q000382:microbiology; D027981:Symporters / Q000235:genetics; D026801:Synteny
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D027981:Symporters; D011808:Quinone Reductases