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Strain 6GN-30(T), a Gram-stain-negative, aerobic, non-spore-forming, rod-shaped, motile bacterium was isolated from Ephedra sinica roots in the Kumtag Desert. On the basis of the 16S rRNA gene sequence, the isolate represented a member of the genus Mesorhizobium of the family Phyllobacteriaceae. The results of a phylogenetic analysis indicated that 6GN-30(T) was phylogenetically related to Mesorhizobium soli NHI-8(T). Strain 6GN-30 T grew at a salinity of 0-1.0% (w/v) NaCl (with optimum growth in the absence of NaCl), pH 6.0-9.0 (optimum 7.0-8.0) and 15-45 degrees C. The major cellular fatty acids were summed feature 8 (C-18:1 omega 7c/C-18:1 omega 6c), C-19:0cyclo omega 8c, iso-C-17:0, C-18:0, and C-16 :0. The draft genome of 6GN-30(T) was 6.11 Mb long, with a DNA G+C content of 66.4 mol%. The average nucleotide identity to M. soli NHI-8(T) was 84.32 %. The strain contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, aminophospholipids and phospholipids. The chemotaxonomic, phylogenetic and phenotypic data indicate that 6GN-30(T) represents a novel species of the genus Mesorhizobium for which the name Mesorhizobium ephedrae sp. nov. is proposed. The type strain is 6GN-30(T) (= ACCC 60073(T) = KCTC 62410(T)).