title: Burkholderia species are ancient symbionts of legumes.
abstract: Burkholderia has only recently been recognized as a potential nitrogen-fixing symbiont of legumes, but we find that the origins of symbiosis in Burkholderia are much deeper than previously suspected. We sampled 143 symbionts from 47 native species of Mimosa across 1800 km in central Brazil and found that 98% were Burkholderia. Gene sequences defined seven distinct and divergent species complexes within the genus Burkholderia. The symbiosis-related genes formed deep Burkholderia-specific clades, each specific to a species complex, implying that these genes diverged over a long period within Burkholderia without substantial horizontal gene transfer between species complexes.
authors.affiliation: Department of Biology, University of York, PO Box 373, York YO10 5YW, England, UK.
authors.forename: Cyril
authors.initials: C
authors.lastname: Bontemps
authors.forename: Geoffrey N
authors.initials: GN
authors.lastname: Elliott
authors.forename: Marcelo F
authors.initials: MF
authors.lastname: Simon
authors.forename: Fábio B
authors.initials: FB
authors.lastname: Dos Reis Júnior
authors.forename: Eduardo
authors.initials: E
authors.lastname: Gross
authors.forename: Rebecca C
authors.initials: RC
authors.lastname: Lawton
authors.forename: Nicolau Elias
authors.initials: NE
authors.lastname: Neto
authors.forename: Maria
authors.initials: M
authors.lastname: de Fátima Loureiro
authors.forename: Sergio M
authors.initials: SM
authors.lastname: De Faria
authors.forename: Janet I
authors.initials: JI
authors.lastname: Sprent
authors.forename: Euan K
authors.initials: EK
authors.lastname: James
authors.forename: J Peter W
authors.initials: JP
authors.lastname: Young
mesh_terms: D001938:Brazil; D019117:Burkholderia / Q000145:classification / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D005843:Geography; D031298:Mimosa / Q000382:microbiology*; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial