Bradyrhizobium campsiandraesp. nov., a nitrogen-fixing bacterial strain isolated from a native leguminous tree from the Amazon adapted to flooded conditions

The nitrogen-fixing bacterial strain UFLA 01-1174(T)was isolated from nodules ofCampsiandra laurilifoliaBenth. originating from the Amazon region, Brazil. Its taxonomic position was defined using a polyphasic approach. Analysis of the 16S rRNA gene placed the strain in theBradyrhizobiumgenus, the closest species beingB. guangdongenseCCBAU 51649(T)andB. guangzhouenseCCBAU 51670(T), both with 99.8% similarity. Multilocus sequence analysis (MLSA) ofrecA,gyrB,glnII,rpoB,atpD, anddnaKindicated that UFLA 01-1174(T )is a new species, most closely related toB. stylosanthisBR 446(T)(94.4%) andB. manausenseBR 3351(T)(93.7%). Average nucleotide identity (ANI) differentiated UFLA 01-1174(T)from the closest species with values lower than 90%. The G + C content in the DNA of UFLA 01-1174(T )is 63.6 mol%. Based on this data, we conclude that the strain represents a new species. The name proposed isBradyrhizobium campsiandrae, with UFLA 01-1174(T)(= INPA 394B(T) = LMG 10099(T)) as type strain

Bradyrhizobium uaiense sp. nov., a new highly efficient cowpea symbiont

This study describes two Bradyrhizobium strains, UFLA03-164(T) and UFLA03-153, which share more than 99% sequence similarity of the 16S rRNA with the type strains of 15 species in this genus. The concatenation of three housekeeping genes (recA, gyrB, and dnaK) indicated that both strains formed a single clade separate from known Bradyrhizobium species. B. viridifuturi, represented by SEMIA 690(T), is the closest neighboring species (96.2%). Low (< 92%) average nucleotide identity (ANI) was observed between strain UFLA03-164(T) and any of the closest species on the phylogenetic trees based on concatenated housekeeping genes. The DNA G+C content of UFLA03-164(T) is 63.25%. Phenotypic characteristics were determined for both UFLA strains. Based on the data, the two strains represent a new species for which the name Bradyrhizobium uaiense is proposed, with UFLA03-164(T) (= LMG 31509(T)) as type strain

Bradyrhizobium forestalis sp. nov., an efficient nitrogen-fixing bacterium isolated from nodules of forest legume species in the Amazon

Three strains of nitrogen-fixing bacteria isolated from nodules of Inga sp. (INPA54B(T)) and Swartzia sp. (INPA86A and INPA01-91A) in soils under native forest in the Brazilian Amazon were previously identified as belonging to the Bradyrhizobium genus. In this study, these strains were characterized using a polyphasic approach to establish their taxonomic position. The three strains shared more than 99.5% sequence similarity of the 16S rRNA gene with the type strains of five Bradyrhizobium species (B. japonicum USDA 6(T), B. liaoningense LMG 18230(T), B. ottawaense OO99(T), B. subterraneum 58 2-1(T) and B. yuanmingense LMG 21827(T)). However, multilocus sequence analysis of two (recA and glnII) or three (atpD, gyrB, and recA) housekeeping genes indicated that these three strains represent a new Bradyrhizobium species, which is closely related to B. subterraneum 58 2-1(T) and B. yuanmingense LMG 21827(T). DNA-DNA hybridization values between INPA54B(T) and B. subterraneum 58 2-1(T) and B. yuanmingense LMG 21827(T) were only 41.5 and 30.9%, respectively. Phenotypic characterization also allowed the differentiation of the novel species from B. subterraneum 58 2-1(T) and B. yuanmingense LMG 21827(T). In the phylogenetic analysis of the nodC and nifH genes, the three strains showed similar sequences that were divergent from those of type strains of all Bradyrhizobium species. We concluded that these strains represent a novel species, for which the name Bradyrhizobium forestalis is proposed, with INPA54B(T) (= LMG 10044(T)) as type strain. The G+C content in the DNA of INPA54B(T) is 63.7 mol%

Bradyrhizobium brasilense sp. nov., a symbiotic nitrogen-fixing bacterium isolated from Brazilian tropical soils

Four strains of rhizobia isolated from nodules of Vigna unguiculata (UFLA03-321(T), UFLA03-320 and UFLA03-290) and Macroptilium atropurpureum (UFLA04-0212) in Brazilian soils were previously reported as a new group within the genus Bradyrhizobium. To determine their taxonomic position, these strains were characterized in this study using a polyphasic approach. The analysis of the 16S rRNA gene grouped the four strains with Bradyrhizobium pachyrhizi PAC48(T). However, the concatenated sequence analysis of the two (recA and glnII) or three (atpD, gyrB and recA) housekeeping genes indicated that these strains represent a novel species of Bradyrhizobium, which is very closely related to B. pachyrhizi PAC48(T) and B. elkanii USDA 76(T). Genomic relatedness analyses between the UFLA03-321(T) strain and B. elkanii USDA 76(T) and B. pachyrhizi PAC48(T) revealed an average nucleotide identity below 96% and values of estimated DNA-DNA hybridization below 70%, confirming that they represent genomically distinct species. Analysis of MALDI-TOF MS (Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry) profiles and phenotypic characteristics also allowed differentiation of the novel species from its two neighboring species. In phylogenetic analysis of nodC and nifH genes, UFLA03-321(T) exhibited maximum similarity with B. tropiciagri CNPSo 1112(T). The data suggest that these four UFLA strains represent a novel species, for which the name Bradyrhizobium brasilense sp. nov. is proposed, with UFLA03-321(T) (=LMG 29353 =CBAS645) as type strain. G + C content in the DNA of UFLA03-321(T) is 63.9 mol %