Twenty-four 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 , IGS, and genes. Genospecies VII was most related to , while genospecies V and VI were both most closely related to , but were distinct from each other and from . The DNA–DNA hybridization value between the representative strain CCBAU 83284 (genospecies VII) and the type strain of was 90.1 %. Genospecies VII was thus defined as . 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 83330) and of VI (CCBAU 83306) were also observed. Based upon these results, two novel species are proposed: sp. nov. represented by genospecies V (type strain, CCBAU 83330=LMG 23949=HAMBI 2974) and sp. nov. represented by genospecies VI (type strain, CCBAU 83306=LMG 24338=HAMBI 2973). 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 , and 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 . As only one strain has been isolated to date, strain CCBAU 83278 was not proposed as a novel species in this study. sp. nov. and sp. nov. could be differentiated from each other as well as from recognized species of the genus on the basis of phenotypic characteristics. The symbiotic loci ( and ) of the two novel species formed two phylogenetic branches related to and . The type strains of the two novel species were able to nodulate , , and but not , , , or .


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Dendrograms constructed from IGS-RFLP, BOX-PCR and SDS-PAGE analyses and additional phylogenetic trees based on IGS, , , and gene sequences. [ PDF] 319 KB


Fatty acid profiles of sp. nov. and sp. nov. in comparison with the closest related taxa. [ PDF] 137 KB

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