title: Microvirga vignae sp. nov., a root nodule symbiotic bacterium isolated from cowpea grown in semi-arid Brazil.
abstract: 16S rRNA gene sequence analysis of eight strains (BR 3299(T), BR 3296, BR 10192, BR 10193, BR 10194, BR 10195, BR 10196 and BR 10197) isolated from nodules of cowpea collected from a semi-arid region of Brazil showed 97 % similarity to sequences of recently described rhizobial species of the genus Microvirga. Phylogenetic analyses of four housekeeping genes (gyrB, recA, dnaK and rpoB), DNA-DNA relatedness and AFLP further indicated that these strains belong to a novel species within the genus Microvirga. Our data support the hypothesis that genes related to nitrogen fixation were obtained via horizontal gene transfer, as sequences of nifH genes were very similar to those found in members of the genera Rhizobium and Mesorhizobium, which are not immediate relatives of the genus Microvirga, as shown by 16S rRNA gene sequence analysis. Phenotypic traits, such as host range and carbon utilization, differentiate the novel strains from the most closely related species, Microvirga lotononidis, Microvirga zambiensis and Microvirga lupini. Therefore, these symbiotic nitrogen-fixing bacteria are proposed to be representatives of a novel species, for which the name Microvirga vignae sp. nov. is suggested. The type strain is BR3299(T) ( = HAMBI 3457(T)).
authors.affiliation: Embrapa Agrobiologia, Rodovia BR 465 km 07, Seropédica 23891-000, Brazil.
authors.forename: Viviane
authors.initials: V
authors.lastname: Radl
authors.affiliation: Embrapa Agrobiologia, Rodovia BR 465 km 07, Seropédica 23891-000, Brazil.
authors.forename: Jean Luiz
authors.initials: JL
authors.lastname: Simões-Araújo
authors.affiliation: Departamento de Solos - Universidade Federal Rural do Rio de Janeiro, Rodovia BR 465 km 07, Seropédica 23891-000, Brazil.
authors.forename: Jakson
authors.initials: J
authors.lastname: Leite
authors.affiliation: Departamento de Solos - Universidade Federal Rural do Rio de Janeiro, Rodovia BR 465 km 07, Seropédica 23891-000, Brazil.
authors.forename: Samuel Ribeiro
authors.initials: SR
authors.lastname: Passos
authors.affiliation: Universidade do Estado da Bahia (UNEB), Departmento de Tecnologia e Ciências Sociais. Avenida Edgard Chastinet, s/n, Juazeiro 48900-000, Brazil.
authors.forename: Lindete Míria Vieira
authors.initials: LMV
authors.lastname: Martins
authors.affiliation: Embrapa Agrobiologia, Rodovia BR 465 km 07, Seropédica 23891-000, Brazil.
authors.forename: Gustavo Ribeiro
authors.initials: GR
authors.lastname: Xavier
authors.affiliation: Embrapa Agrobiologia, Rodovia BR 465 km 07, Seropédica 23891-000, Brazil.
authors.forename: Norma Gouvêa
authors.initials: NG
authors.lastname: Rumjanek
authors.affiliation: Embrapa Agrobiologia, Rodovia BR 465 km 07, Seropédica 23891-000, Brazil.
authors.forename: José Ivo
authors.initials: JI
authors.lastname: Baldani
authors.affiliation: Embrapa Agrobiologia, Rodovia BR 465 km 07, Seropédica 23891-000, Brazil.
authors.forename: Jerri Edson
authors.initials: JE
authors.lastname: Zilli
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D015373:Bacterial Typing Techniques; D001938:Brazil; D004269:DNA, Bacterial / Q000235:genetics; D007887:Fabaceae / Q000382:microbiology*; D005798:Genes, Bacterial; D042082:Methylobacteriaceae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D053204:Root Nodules, Plant / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S