Phenotypic characterization of Astragalus glycyphyllos symbionts and their phylogeny based on the 16S rDNA sequences and RFLP of 16S rRNA gene.
In this study, the nitrogen fixing Astragalus glycyphyllos symbionts were characterized by phenotypic properties, restriction fragment length polymorphism (RFLP), and sequences of 16S rDNA. The generation time of A. glycyphyllos rhizobia in yeast extract mannitol medium was in the range 4-6 h. The studied isolates exhibited a low resistance to antibiotics, a moderate tolerance to NaCl, assimilated di- and trisaccharides, and produced acid in medium containing mannitol as a sole carbon source. In the cluster analysis, based on 86 phenotypic properties of A. glycyphyllos symbionts and the reference rhizobia, examined isolates and the genus Mesorhizobium strains were placed on a single branch, clearly distinct from other lineages of rhizobial genera. By the comparative analysis of 16S rRNA gene sequences and 16S rDNA-RFLP, A. glycyphyllos nodulators were also identified as the members of the genus Mesorhizobium. On the 16S rDNA sequence phylogram, the representatives of A. glycyphyllos nodule isolates formed a robust, monophyletic cluster together with the Mesorhizobium species at 16S rDNA sequence similarity of these bacteria between 95 and 99 %. Similarly, the cluster analysis of the combined RFLP-16S rDNA patterns, obtained with seven restriction endonucleases, showed that A. glycyphyllos rhizobia are closely related to the genus Mesorhizobium bacteria. The taxonomic approaches used in this paper allowed us to classify the studied bacteria into the genus Mesorhizobium.
Department of Veterinary Microbiology, University of Life Sciences, 12 Akademicka st., 20-033, Lublin, Poland.
Sebastian
S
Gnat
Magdalena
M
Wójcik
Sylwia
S
Wdowiak-Wróbel
Michał
M
Kalita
Aneta
A
Ptaszyńska
Wanda
W
Małek
D015373:Bacterial Typing Techniques; D002264:Carboxylic Acids / Q000378:metabolism; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D007887:Fabaceae / Q000382:microbiology*; D020459:Genes, rRNA; D008353:Mannitol / Q000378:metabolism; D059128:Mesorhizobium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000378:metabolism; D013559:Symbiosis
D002264:Carboxylic Acids; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D008353:Mannitol; D012965:Sodium Chloride