title: The genome of Bacillus coahuilensis reveals adaptations essential for survival in the relic of an ancient marine environment.
abstract: The Cuatro Ciénegas Basin (CCB) in the central part of the Chihuahan desert (Coahuila, Mexico) hosts a wide diversity of microorganisms contained within springs thought to be geomorphological relics of an ancient sea. A major question remaining to be answered is whether bacteria from CCB are ancient marine bacteria that adapted to an oligotrophic system poor in NaCl, rich in sulfates, and with extremely low phosphorus levels (<0.3 microM). Here, we report the complete genome sequence of Bacillus coahuilensis, a sporulating bacterium isolated from the water column of a desiccation lagoon in CCB. At 3.35 Megabases this is the smallest genome sequenced to date of a Bacillus species and provides insights into the origin, evolution, and adaptation of B. coahuilensis to the CCB environment. We propose that the size and complexity of the B. coahuilensis genome reflects the adaptation of an ancient marine bacterium to a novel environment, providing support to a "marine isolation origin hypothesis" that is consistent with the geology of CCB. This genomic adaptation includes the acquisition through horizontal gene transfer of genes involved in phosphorous utilization efficiency and adaptation to high-light environments. The B. coahuilensis genome sequence also revealed important ecological features of the bacterial community in CCB and offers opportunities for a unique glimpse of a microbe-dominated world last seen in the Precambrian.
authors.affiliation: Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Departamento de Ingeniería Genética and Departamento de Biotecnología, Cinvestav, Campus Guanajuato, AP 629 Irapuato, Guanajuato CP36500, México.
authors.forename: Luis David
authors.initials: LD
authors.lastname: Alcaraz
authors.forename: Gabriela
authors.initials: G
authors.lastname: Olmedo
authors.forename: Germán
authors.initials: G
authors.lastname: Bonilla
authors.forename: René
authors.initials: R
authors.lastname: Cerritos
authors.forename: Gustavo
authors.initials: G
authors.lastname: Hernández
authors.forename: Alfredo
authors.initials: A
authors.lastname: Cruz
authors.forename: Enrique
authors.initials: E
authors.lastname: Ramírez
authors.forename: Catherine
authors.initials: C
authors.lastname: Putonti
authors.forename: Beatriz
authors.initials: B
authors.lastname: Jiménez
authors.forename: Eva
authors.initials: E
authors.lastname: Martínez
authors.forename: Varinia
authors.initials: V
authors.lastname: López
authors.forename: Jacqueline L
authors.initials: JL
authors.lastname: Arvizu
authors.forename: Francisco
authors.initials: F
authors.lastname: Ayala
authors.forename: Francisco
authors.initials: F
authors.lastname: Razo
authors.forename: Juan
authors.initials: J
authors.lastname: Caballero
authors.forename: Janet
authors.initials: J
authors.lastname: Siefert
authors.forename: Luis
authors.initials: L
authors.lastname: Eguiarte
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Vielle
authors.forename: Octavio
authors.initials: O
authors.lastname: Martínez
authors.forename: Valeria
authors.initials: V
authors.lastname: Souza
authors.forename: Alfredo
authors.initials: A
authors.lastname: Herrera-Estrella
authors.forename: Luis
authors.initials: L
authors.lastname: Herrera-Estrella
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D001407:Bacillus / Q000235:genetics*; D001483:Base Sequence; D005075:Biological Evolution; D004777:Environment; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D008027:Light; D008969:Molecular Sequence Data; D010758:Phosphorus / Q000378:metabolism; D012623:Seawater
chemical_list: D010758:Phosphorus