title: Endosymbiotic bacteria nodulating a new endemic lupine Lupinus mariae-josephi from alkaline soils in Eastern Spain represent a new lineage within the Bradyrhizobium genus.
abstract: Lupinus mariae-josephi is a recently described endemic Lupinus species from a small area in Eastern Spain where it thrives in soils with active lime and high pH. The L. mariae-josephi root symbionts were shown to be very slow-growing bacteria with different phenotypic and symbiotic characteristics from those of Bradyrhizobium strains nodulating other Lupinus. Their phylogenetic status was examined by multilocus sequence analyses of four housekeeping genes (16S rRNA, glnII, recA, and atpD) and showed the existence of a distinct evolutionary lineage for L. mariae-josephi that also included Bradyrhizobium jicamae. Within this lineage, the tested isolates clustered in three different sub-groups that might correspond to novel sister Bradyrhizobium species. These core gene analyses consistently showed that all the endosymbiotic bacteria isolated from other Lupinus species of the Iberian Peninsula were related to strains of the B. canariense or B. japonicum lineages and were separate from the L. mariae-josephi isolates. Phylogenetic analysis based on nodC symbiotic gene sequences showed that L. mariae-josephi bacteria also constituted a new symbiotic lineage distant from those previously defined in the genus Bradyrhizobium. In contrast, the nodC genes of isolates from other Lupinus spp. from the Iberian Peninsula were again clearly related to the B. canariense and B. japonicum bv. genistearum lineages. Speciation of L. mariae-josephi bradyrhizobia may result from the colonization of a singular habitat by their unique legume host.
authors.affiliation: Departamento de Biotecnología (ETS de Ingenieros Agrónomos) and Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid, 28040 Madrid, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Sánchez-Cañizares
authors.forename: Luis
authors.initials: L
authors.lastname: Rey
authors.forename: David
authors.initials: D
authors.lastname: Durán
authors.forename: Francisco
authors.initials: F
authors.lastname: Temprano
authors.forename: Paloma
authors.initials: P
authors.lastname: Sánchez-Jiménez
authors.forename: Albert
authors.initials: A
authors.lastname: Navarro
authors.forename: Mira
authors.initials: M
authors.lastname: Polajnar
authors.forename: Juan
authors.initials: J
authors.lastname: Imperial
authors.forename: Tomás
authors.initials: T
authors.lastname: Ruiz-Argüeso
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D020369:Bradyrhizobium / Q000145:classification* / Q000235:genetics / Q000502:physiology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D058507:Host Specificity; D006863:Hydrogen-Ion Concentration; D031297:Lupinus / Q000382:microbiology* / Q000502:physiology*; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D055170:Plant Root Nodulation; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011938:Rec A Recombinases / Q000235:genetics; D053204:Root Nodules, Plant / Q000382:microbiology; D017422:Sequence Analysis, DNA; D012987:Soil / Q000737:chemistry; D013030:Spain; D013559:Symbiosis / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012987:Soil; D017351:N-Acetylglucosaminyltransferases; C060771:NodC protein, Rhizobiales; D011938:Rec A Recombinases