Tardiphaga robiniae gen. nov., sp. nov., a new genus in the family Bradyrhizobiaceae isolated from Robinia pseudoacacia in Flanders (Belgium)

Gram-negative, rod-shaped bacteria were isolated from Robinia pseudoacacia root nodules. On the basis of the 16S rRNA gene phylogeny, they are closely related to Bradyrhizobium, Rhodopseudomonas and Nitrobacter species (97% sequence similarity), belonging to the class Alphaproteobacteria and family Bradyrhizobiaceae. The results of physiological and biochemical tests together with sequence analysis of housekeeping genes (atpD, dnaK, gyrB, recA and rpoB) allowed differentiation of this group from other validly published Bradyrhizobiaceae genera. NodA, nodC and nifH genes could not be amplified. On the basis of genotypic and phenotypic data, these organisms represent a novel genus and species for which the name Tardiphaga robiniae gen. nov., sp. nov. (LMG 26467T = CCUG 61473T), is proposed.