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Rhizobium sphaerophysae sp. nov., a novel species isolated from root nodules of Sphaerophysa salsula in China

Xu, Lin, Shi, Jian Feng, Zhao, Peng, Chen, Wei Min, Qin, Wei, Tang, Ming, Wei, Ge Hong
Antonie van Leeuwenhoek 2011 v.99 no.4 pp. 845-854
Rhizobium giardinii, Sphaerophysa salsula, new species, nucleotide sequences, pH, phylogeny, ribosomal RNA, root nodules, China
Four gram-negative, aerobic, motile, non-spore, forming rods with a wide pH and temperature range for growth (pH 7.0-11.0, optimum pH 8.0; 20-45°C, optimum 28°C) strains were isolated from root nodules of Sphaerophysa salsula and characterized by means of a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the four strains formed a new lineage related to the genus Rhizobium and the sequence similarities between the isolate and the most related type strain Rhizobium giardinii was 96.5%. These strains also formed a distinctive group from the reference strains for defined Rhizobium species based on housekeeping gene sequences (atpD and recA), BOX-PCR fingerprinting, phenotypic features and symbiotic properties. The representative strain CCNWGS0238T has DNA-DNA relatedness of less than 33.4% with the most closely related species R. giardinii. It is therefore proposed as a new species, Rhizobium sphaerophysae sp. nov., with isolate CCNWGS0238T (=ACCC17498T = HAMBI3074T) as the type strain.