Isolation and characterization of rhizobia from nodules of Clitoria ternatea in Thailand.

Rhizobia were isolated from the root nodules of Clitoria ternatea in Thailand. The phylogeny of the isolates was investigated using 16S rDNA and the internal transcribed spacer (ITS) region from 16S to 23S rDNA. The phylogenetic tree of the 16S rDNA showed that ten of the eleven isolates belonged to Bradyrhizobium elkanii, and one belonged to Bradyrhizobium japonicum. The topology of the ITS tree was similar to that of 16S rDNA. The acetylene reduction activity was higher for the nodules inoculated with the isolated B. elkanii strains than for those inoculated with B. japonicum strains. When C. ternatea plants were inoculated with various Bradyrhizobium USDA strains isolated from Glycine max, C. ternatea formed many effective nodules with B. elkanii, especially USDA61. However, acetylene reduction activity per plant and the growth were higher in C. ternatea inoculated with our isolates. From these data we propose that effective rhizobia inoculant were identified for C. ternatea cultivation.