Comparison of phylogeny analysis methods for rhizobia Albizia spp., Acacia spp. and Leucaena leucocephala
合欢、金合欢和银合欢根瘤菌系统发育研究方法比较

Multilocus house-keeping gene sequence analysis is a hotspot of taxonomy and phylogeny of prokaryotes. In this research, we used atpD and gln II gene sequences to analyze the phylogeny of nine rhizobia strains of Albizia spp., Acacia spp. and Leucaena leucocephala and compared the results to that of 16S rDNA. The phylogenetic relationships based on the sequence analysis of these three genes were congruent at the genera level. CCBAU43060 and CCBAU 61139 were located in the branch of Rhizobium-Agrobacterium. CCBAU51471, CCBAU35220, CCBAU51276 and CCBAU61158 belonged to the genera of Mesorhizobium. CCBAU35234, CCBAU61178 and CCBAU35085 were assigned to Bradyrhizobium. Differences were found for some strains, for example CCBAU 61158, CCBAU43060, CCBAU61178, at the species level. Insertion fragment and mosaic gene were also found in some isolates. These results indicated that there was recombination between species in the same genera. It is reliable to determine the taxonomy status at genera levels based on the sequence analysis of 16S rDNA. If the relationships between strains belonging to the same genera were studied using the phylogeny methods, researches should be carded out with more than one house-keeping genes.