title: Definition of a novel symbiovar (sv. retamae) within Bradyrhizobium retamae sp. nov., nodulating Retama sphaerocarpa and Retama monosperma.
abstract: In this paper we analyze through a polyphasic approach several Bradyrhizobium strains isolated in Spain and Morocco from root nodules of Retama sphaerocarpa and Retama monosperma. All the strains have identical 16S rRNA genes and their closest relative species is Bradyrhizobium lablabi CCBAU 23086(T), with 99.41% identity with respect to the strain Ro19(T). Despite the closeness of the 16S rRNA genes, the housekeeping genes recA, atpD and glnII were divergent in Ro19(T) and B. lablabi CCBAU 23086(T), with identity values of 95.71%, 93.75% and 93.11%, respectively. These differences were congruent with DNA-DNA hybridization analysis that revealed an average of 35% relatedness between the novel species and B. lablabi CCBAU 23086(T). Also, differential phenotypic characteristics of the new species were found with respect to the already described species of Bradyrhizobium. Based on the genotypic and phenotypic data obtained in this study, we propose to classify the group of strains isolated from R. sphaerocarpa and R. monosperma as a novel species named Bradyrhizobium retamae sp. nov. (type strain Ro19(T)=LMG 27393(T)=CECT 8261(T)). The analysis of symbiotic genes revealed that some of these strains constitute a new symbiovar within genus Bradyrhizobium for which we propose the name "retamae", that mainly contains nodulating strains isolated from Retama species in different continents.
authors.affiliation: Laboratoire de Biologie des Plantes et des Microorganismes, Faculté des Sciences, Université Mohamed Premier, Oujda, Morocco.
authors.forename: Kamal
authors.initials: K
authors.lastname: Guerrouj
authors.forename: Beatriz
authors.initials: B
authors.lastname: Ruíz-Díez
authors.forename: Rajaa
authors.initials: R
authors.lastname: Chahboune
authors.forename: Martha-Helena
authors.initials: MH
authors.lastname: Ramírez-Bahena
authors.forename: Hanaa
authors.initials: H
authors.lastname: Abdelmoumen
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Quiñones
authors.forename: Mustapha Missbah
authors.initials: MM
authors.lastname: El Idrissi
authors.forename: Encarna
authors.initials: E
authors.lastname: Velázquez
authors.forename: Mercedes
authors.initials: M
authors.lastname: Fernández-Pascual
authors.forename: Eulogio J
authors.initials: EJ
authors.lastname: Bedmar
authors.forename: Alvaro
authors.initials: A
authors.lastname: Peix
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D020369:Bradyrhizobium / Q000145:classification* / Q000302:isolation & purification*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D007887:Fabaceae / Q000382:microbiology*; D020043:Genes, Essential; D008969:Molecular Sequence Data; D009018:Morocco; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D053204:Root Nodules, Plant / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013030:Spain
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S