Diagnosis of mungbean (Vigna radiate) bradyrhizobia isolated from Kyushu Island of Japan based on whole cellular fatty acid analysis

Previous studies have already reported that cellular fatty acid analysis is a useful taxonomic tool for classifying and identifying Bradyrhizobium strains. In this study, the fatty acid profiles of 13 strains of MAFF collections and 36 strains collected from Fukuoka, Saga, Oita, Kumamoto and Kagoshima Prefecture belonging to unknown species of Bradyrhizobium were evaluated. Total 11 fatty acids were identified and qualitative and quantitative variations of fatty acid compositions were observed. Data of fatty acid compositions obtained from each strain was statistically investigated by PCA and PCGMA clustering. Statistical analysis showed that the dominant five distinct clusters were formed and conveniently grouped as FAG-I to FAG-V. FAG-I and FAG-II strains were closely relationships to the strain of B. elkanii. FAG-III and FAG-V strains were relevant to the strain of B. japonicum. On the other hand, FAG-IV strains isolated from mungbean root nodules were clustered with B. japonicum FAG-III and FAG-V but obviously different compositions of fatty acid and distinguishable to these two subgroups.