Phylogenetically clustering of rhizobial reference strains based on numbers and location of their 23S rRNA genes
根瘤菌参比菌株23S rRNA基因数量和定位及其系统发育群

To clarify phylogenetic relationships among rhizobial reference strains,the numbers and location of their 23S rRNA genes were analyzed by pulsed field gel electrophoresis(PFGE) after I-CeuI cleavage.According to the similarity in the numbers and location of their 23S rRNA genes,rhizobial reference strains were grouped into 19 phylogenetic clusters.Of which,13 clusters were consistent with taxonomic groupings(taxa) in genera level,but 6 clusters not.The clustering method based on the numbers and location of rhizobial 23S rRNA genes also divided the rhizobia belonging to the same taxa into different phylogenetic clusters.These results suggest that identification of genomic features using PFGE after DNA cleavage with I-CeuI can further characterize current rhizobial taxa into different phylogenetic clusters with a high genetic homogeneity inside clusters.