title: Reclassification of Rhizobium tropici type A strains as Rhizobium leucaenae sp. nov.
abstract: Rhizobium tropici is a well-studied legume symbiont characterized by high genetic stability of the symbiotic plasmid and tolerance to tropical environmental stresses such as high temperature and low soil pH. However, high phenetic and genetic variabilities among R. tropici strains have been largely reported, with two subgroups, designated type A and B, already defined within the species. A polyphasic study comprising multilocus sequence analysis, phenotypic and genotypic characterizations, including DNA-DNA hybridization, strongly supported the reclassification of R. tropici type A strains as a novel species. Type A strains formed a well-differentiated clade that grouped with R. tropici, Rhizobium multihospitium, Rhizobium miluonense, Rhizobium lusitanum and Rhizobium rhizogenes in the phylogenies of the 16S rRNA, recA, gltA, rpoA, glnII and rpoB genes. Several phenotypic traits differentiated type A strains from all related taxa. The novel species, for which the name Rhizobium leucaenae sp. nov. is proposed, is a broad host range rhizobium being able to establish effective root-nodule symbioses with Leucaena leucocephala, Leucaena esculenta, common beans (Phaseolus vulgaris) and Gliricidia sepium. Strain CFN 299(T) ( = USDA 9039(T) = LMG 9517(T) = CECT 4844(T) = JCM 21088(T) = IAM 14230(T) = SEMIA 4083(T) = CENA 183(T) = UMR1026(T) = CNPSo 141(T)) is designated the type strain of Rhizobium leucaenae sp. nov.
authors: Universidade Estadual de Londrina, Department of Microbiology, Cx. Postal 60001, 86051-990, Londrina, Paraná, Brazil.|Embrapa Soja, Cx. Postal 231, 86001-970, Londrina, Paraná, Brazil.
authors: Renan Augusto
authors: RA
authors: Ribeiro
authors: Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.
authors: Marco A
authors: MA
authors: Rogel
authors: Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.
authors: Aline
authors: A
authors: López-López
authors: Embrapa Soja, Cx. Postal 231, 86001-970, Londrina, Paraná, Brazil.
authors: Ernesto
authors: E
authors: Ormeño-Orrillo
authors: Universidade Paranaense - UNIPAR, Cx. Postal 224, 87502-210, Umuarama, Paraná, Brazil.
authors: Fernando Gomes
authors: FG
authors: Barcellos
authors: Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.
authors: Julio
authors: J
authors: Martínez
authors: UFRJ, Center of Health Sciences, Institute of Biology, Cx. Postal 68011, 21944-970, Rio de Janeiro, Brazil.
authors: Fabiano Lopes
authors: FL
authors: Thompson
authors: Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.
authors: Esperanza
authors: E
authors: Martínez-Romero
authors: Embrapa Soja, Cx. Postal 231, 86001-970, Londrina, Paraná, Brazil.
authors: Mariangela
authors: M
authors: Hungria
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D042162:Rhizobium tropici / Q000145:classification* / Q000235:genetics* / Q000502:physiology; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S