Estimation of the bacterial community diversity of soybean-nodulating bradyrhizobia isolated fromRj-genotype soybeans

The diversities of communities of soybean-nodulating indigenous bradyrhizobia in Japan were estimated using mathematical ecology methods based on the results of polymerase chain reaction–restriction fragment length polymorphism analysis of the 16S–23S rDNA internal-transcribed spacer region. Polar ordination analysis indicated a significant correlation between the compositions of bradyrhizobial communities and northern latitudes in Japan. This result suggests that the composition and the geographical distribution of indigenous soybean-nodulating bradyrhizobia might be affected by soil temperature and the associated diversity of the host plants acclimatized to a particular climate. Furthermore, for estimation of the compositional difference in bacterial communities among three different Rj-genotype soybean cultivars, an analysis of the diversity indexes was conducted and this analysis indicated differences in the composition of the communities isolated from the Rj 2 Rj 3-genotype compared with those from the non-Rj- and Rj 4-genotype cultivars. This result suggests that Rj 2 Rj 3-genotype soybeans might affect not only compatibility with particular bradyrhizobia, but also preference to bradyrhizobia for nodulation.