Mesorhizobium alhagi sp. nov., isolated from wild Alhagi sparsifolia in north-western China.

Eleven strains that formed symbiotic root nodules on Alhagi sparsifolia, designated previously as genospecies II, were identified as a new lineage of Mesorhizobium (Alphaproteobacteria) that could be differentiated from all previously recognized species of the genus Mesorhizobium by using 16S rRNA gene sequences (<97.8 % similarity), DNA-DNA hybridization (<45 %), dnaJ, dnaK, recA, glnA, nifH, nodA and nodC gene sequences, fatty acid profiles (C(18 : 1)omega7c, 35 %;11-methyl C(18 : 1)omega7c, 30 %) and numerical taxonomy. These strains are therefore considered to represent a novel species, for which the name Mesorhizobium alhagi sp. nov. is proposed, with isolate CCNWXJ12-2(T) (=ACCC 15461(T)=HAMBI 3019(T)) as the type strain.