title: Phylogeny of the Rhizobium-Allorhizobium-Agrobacterium clade supports the delineation of Neorhizobium gen. nov.
abstract: The genera Agrobacterium, Allorhizobium, and Rhizobium belong to the family Rhizobiaceae. However, the placement of a phytopathogenic group of bacteria, the genus Agrobacterium, among the nitrogen-fixing bacteria and the unclear position of Rhizobium galegae have caused controversy in previous taxonomic studies. To resolve uncertainties in the taxonomy and nomenclature within this family, the phylogenetic relationships of generic members of Rhizobiaceae were studied, but with particular emphasis on the taxa included in Agrobacterium and the "R. galegae complex" (R. galegae and related taxa), using multilocus sequence analysis (MLSA) of six protein-coding housekeeping genes among 114 rhizobial and agrobacterial taxa. The results showed that R. galegae, R. vignae, R. huautlense, and R. alkalisoli formed a separate clade that clearly represented a new genus, for which the name Neorhizobium is proposed. Agrobacterium was shown to represent a separate cluster of mainly pathogenic taxa of the family Rhizobiaceae. A. vitis grouped with Allorhizobium, distinct from Agrobacterium, and should be reclassified as Allorhizobium vitis, whereas Rhizobium rhizogenes was considered to be the proper name for former Agrobacterium rhizogenes. This phylogenetic study further indicated that the taxonomic status of several taxa could be resolved by the creation of more novel genera.
authors.affiliation: University of Helsinki, Division of Microbiology and Biotechnology, Department of Food and Environmental Sciences, Biocentre 1, Viikinkaari 9, P.O. Box 56, Helsinki FIN-00014, Finland. Electronic address: seyed.mousavi@helsinki.fi.
authors.forename: Seyed Abdollah
authors.initials: SA
authors.lastname: Mousavi
authors.affiliation: University of Helsinki, Division of Microbiology and Biotechnology, Department of Food and Environmental Sciences, Biocentre 1, Viikinkaari 9, P.O. Box 56, Helsinki FIN-00014, Finland.
authors.forename: Janina
authors.initials: J
authors.lastname: Österman
authors.affiliation: University of Turku, Laboratory of Genetics, Department of Biology, 20014 Turku, Finland.
authors.forename: Niklas
authors.initials: N
authors.lastname: Wahlberg
authors.affiliation: University of Lyon, Université Lyon1, Ecologie Microbienne, UMR CNRS 5557/USC INRA 1364, 16 rue R. Dubois, F-69622 Villeurbanne Cedex, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Nesme
authors.affiliation: University of Lyon, Université Lyon1, Ecologie Microbienne, UMR CNRS 5557/USC INRA 1364, 16 rue R. Dubois, F-69622 Villeurbanne Cedex, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Lavire
authors.affiliation: University of Lyon, Université Lyon1, Ecologie Microbienne, UMR CNRS 5557/USC INRA 1364, 16 rue R. Dubois, F-69622 Villeurbanne Cedex, France.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Vial
authors.affiliation: University of Helsinki, Institute of Biotechnology, DNA Sequencing and Genomics Laboratory, Viikinkaari 4, P.O. Box 56, Helsinki FIN-00014, Finland.
authors.forename: Lars
authors.initials: L
authors.lastname: Paulin
authors.affiliation: IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, Campus de Baillarguet TA A-82/J, 34398 Montpellier Cédex 5, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: de Lajudie
authors.affiliation: University of Helsinki, Division of Microbiology and Biotechnology, Department of Food and Environmental Sciences, Biocentre 1, Viikinkaari 9, P.O. Box 56, Helsinki FIN-00014, Finland; University of Helsinki, Department of Environmental Sciences, Viikinkaari 2a, P.O. Box 65, Helsinki FIN-00014, Finland.
authors.forename: Kristina
authors.initials: K
authors.lastname: Lindström
mesh_terms: D005798:Genes, Bacterial; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D012230:Rhizobiaceae / Q000145:classification* / Q000235:genetics*
keywords: Agrobacterium; Allorhizobium; Housekeeping genes; MLSA; Rhizobium galegae