title: Novel Rhizobium lineages isolated from root nodules of the common bean (Phaseolus vulgaris L.) in Andean and Mesoamerican areas.
abstract: The taxonomic affiliations of nineteen root-nodule bacteria isolated from the common bean (Phaseolus vulgaris L.) in Mexico, Ecuador and Brazil were investigated by analyses of 16S rRNA and of four protein-coding housekeeping genes. One strain from Mexico could be assigned to Rhizobium etli and two from Brazil to Rhizobium leucaenae, whereas another from Mexico corresponded to a recently described bean-nodulating species-level lineage related to R. etli and Rhizobium phaseoli. Ten strains isolated in Ecuador and Mexico corresponded to three novel Rhizobium lineages that fall into the R. phaseoli/R. etli/Rhizobium leguminosarum clade. One of those lineages, with representatives isolated mostly from Ecuador, seems to be dominant in beans from that Andean region. Only one of the Mexican strains clustered within the Rhizobium tropici clade, but as an independent lineage. Interestingly, four strains were affiliated with species within the Rhizobium radiobacter clade. The existence of yet non-described native Rhizobium lineages in both the Andean and Mesoamerican areas is discussed in relation to common-bean diversity and environmental conditions.
authors.affiliation: Universidade Estadual de Londrina, Dept. Microbiology, C.P. 6001, 86051-990 Londrina, Paraná, Brazil. renan.ribeiro@embrapa.br
authors.forename: Renan Augusto
authors.initials: RA
authors.lastname: Ribeiro
authors.forename: Ernesto
authors.initials: E
authors.lastname: Ormeño-Orrillo
authors.forename: Rebeca Fuzinatto
authors.initials: RF
authors.lastname: Dall'Agnol
authors.forename: Peter H
authors.initials: PH
authors.lastname: Graham
authors.forename: Esperanza
authors.initials: E
authors.lastname: Martinez-Romero
authors.forename: Mariangela
authors.initials: M
authors.lastname: Hungria
mesh_terms: D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D014644:Genetic Variation; D008800:Mexico; D008969:Molecular Sequence Data; D027805:Phaseolus / Q000382:microbiology* / Q000502:physiology; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012231:Rhizobium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D053204:Root Nodules, Plant / Q000382:microbiology* / Q000502:physiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S
keywords: 16S rRNA gene; Biological nitrogen fixation; MLSA; Phylogeny; Rhizobium; Symbiosis