Strains nodulating Lupinus albus on different continents belong to several new chromosomal and symbiotic lineages within Bradyrhizobium

摘要

In this work we analysed different chromosomal\udand symbiotic markers in rhizobial strains\udnodulating Lupinus albus (white lupin) in several\udcontinents. Collectively the analysis of their rrs and\udatpD genes, and 16S-23S intergenic spacers (ITS),\udshowed that they belong to at least four chromosomal\udlineages within the genus Bradyrhizobium. Most\udisolates from the Canary Islands (near to the African\udcontinent) grouped with some strains isolated on\udmainland Spain and were identified as Bradyrhizobium\udcanariense. These strains are divided into two ITS\udsubgroups coincident with those previously described\udfrom isolates nodulating Ornithopus. The remaining\udstrains isolated on mainland Spain grouped with most\udisolates from Chile (American continent) forming a\udnew lineage related to Bradyrhizobium japonicum.\udThe strains BLUT2 and ISLU207 isolated from the\udCanary Islands and Chile, respectively, formed two\udnew lineages phylogenetically close to different\udspecies of Bradyrhizobium depending on the marker\udanalyzed. The analysis of the nodC gene showed that\udall strains nodulating L. albus belong to the biovar\udgenistearum; nevertheless they form four different\udnodC lineages of which lineage C is at present\udexclusively formed by L. albus endosymbionts isolated\udfrom different continents.