Bradyrhizobium nivariense sp. nov., predominant species nodulating Cytisus supranubius in the high mountain ecosystem of Tenerife (Canary Islands)

Bradyrhizobial strains nodulate the native legume Cytisus supranubius ( Genisteae ) in its natural habitat: the high-mountain ecosystem of Tenerife (Canary Islands), where nitrogen fixation is an essential activity in its N-poor soils. Three of these strains, SSUT18 T , SSUT77 and SSUT112, are representative of a major phylotype within the genus Bradyrhizobium, and the phylogenetic analysis of their 16S rRNA gene sequences showed that Bradyrhizobium canariense is their closest relative. Nevertheless, the multilocus sequence analysis and the genome analysis distinguished these strains from the type strain of B. canariense and from the remaining species of the genus Bradyrhizobium . The calculated Average Nucleotide Identity (blast) (ANIb) and digital DNA–DNA hybridization values between the genomes of the strains from the new species and B. canariense were also lower than the threshold values proposed for species differentiation. These data, together with differences observed in chemotaxonomic and phenotypic characteristics, support the classification of the strains SSUT18 T , SSUT77 and SSUT112 into a new species of Bradyrhizobium , for which we propose the name Bradyrhizobium nivariense sp. nov. (type strain SSUT18 T =CECT 30998 T =LMG 33353 T ).