RT Journal Article SR Electronic(1) A1 Han, Tian Xu A1 Han, Li Li A1 Wu, Li Juan A1 Chen, Wen Feng A1 Sui, Xin Hua A1 Gu, Jin Gang A1 Wang, En Tao A1 Chen, Wen XinYR 2008 T1 Mesorhizobium gobiense sp. nov. and Mesorhizobium tarimense sp. nov., isolated from wild legumes growing in desert soils of Xinjiang, China JF International Journal of Systematic and Evolutionary Microbiology, VO 58 IS 11 SP 2610 OP 2618 DO https://doi.org/10.1099/ijs.0.2008/000125-0 PB Microbiology Society, SN 1466-5034, AB Twenty-four Mesorhizobium strains were isolated from desert soils in the Xinjiang region of China and were characterized by a polyphasic approach. These strains grouped into three clusters in IGS-RFLP, SDS-PAGE analysis of whole-cell proteins and BOX-PCR analysis, corresponding to genomic species V, VI and VII as found in a previous study. The results were supported by sequencing analyses of rrs, IGS, atpD and recA genes. Genospecies VII was most related to Mesorhizobium septentrionale, while genospecies V and VI were both most closely related to Mesorhizobium tianshanense, but were distinct from each other and from M. tianshanense. The DNA–DNA hybridization value between the representative strain CCBAU 83284 (genospecies VII) and the type strain of M. septentrionale was 90.1 %. Genospecies VII was thus defined as M. septentrionale. The DNA–DNA relatedness value for representative strains of genospecies V or VI with the related reference strains of recognized species were always lower than 60 %. Low values of DNA–DNA hybridization (32.79 %) between representative strains of genospecies V (CCBAU 83330T) and of VI (CCBAU 83306T) were also observed. Based upon these results, two novel species are proposed: Mesorhizobium gobiense sp. nov. represented by genospecies V (type strain, CCBAU 83330T=LMG 23949T=HAMBI 2974T) and Mesorhizobium tarimense sp. nov. represented by genospecies VI (type strain, CCBAU 83306T=LMG 24338T=HAMBI 2973T). Strain CCBAU 83278 grouped as the most peripheral member with genospecies VI in SDS-PAGE of whole-cell proteins and BOX-PCR analysis and in the phylogenetic tree of 16S-23S rRNA intergenic spacer (IGS) sequences. The results of analyses of rrs, atpD and recA gene sequences, as well as those of DNA–DNA hybridization studies, strongly supported the suggestion that this strain belonged to a species quite different from genospecies V and VI and from any other recognized species of the genus Mesorhizobium. As only one strain has been isolated to date, strain CCBAU 83278 was not proposed as a novel species in this study. Mesorhizobium gobiense sp. nov. and Mesorhizobium tarimense sp. nov. could be differentiated from each other as well as from recognized species of the genus Mesorhizobium on the basis of phenotypic characteristics. The symbiotic loci (nodC and nifH) of the two novel species formed two phylogenetic branches related to Mesorhizobium loti and M. tianshanense. The type strains of the two novel species were able to nodulate Glycyrrhiza uralensis, Lotus corniculatus, Oxytropis glabra and Robinia pseudoacacia but not Astragalus membranaceus, Leucaena leucocephala, Phaseolus vulgaris, Pisum sativum or Medicago sativa., UL https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijs.0.2008/000125-0