title: Mesorhizobium sangaii sp. nov., isolated from the root nodules of Astragalus luteolus and Astragalus ernestii.
abstract: Our previous published data indicated that the two rhizobial strains SCAU7(T) and SCAU27, which were isolated from the root nodules of Astragalus luteolus and Astragalus ernestii respectively, in Sichuan Province, China, might be novel species of the genus Mesorhizobium. Their exact taxonomic position was determined in the present study by using polyphasic approaches. Comparative analysis of nearly full-length 16S rRNA gene sequences showed that these strains belonged to the genus Mesorhizobium, with Mesorhizobium ciceri USDA 3383(T), Mesorhizobium loti NZP 2213(T), Mesorhizobium shangrilense CCBAU 65327(T) and Mesorhizobium australicum WSM2073(T) as the closest neighbours (>99 % 16S rRNA gene sequence similarity). Phylogenies of the housekeeping genes atpD and recA confirmed their distinct position, showing low similarity with respect to those of M. loti LMG 6125(T) (96.5 % and 92.3 % similarity respectively), M. ciceri USDA 3383(T) (96.8 % and 93.3 % similarity, respectively), M. shangrilense CCBAU 65327(T) (96.5 % and 92.7 % similarity, respectively) and M. australicum WSM2073(T) (95.4 % and 90.6 % similarity, respectively). The DNA-DNA relatedness values between strain SCAU7(T) and strain SCAU27 were 83.0 %, showing that they belong to the same species. The DNA-DNA relatedness values of SCAU7(T) with M. loti NZP 2213(T), M. ciceri USDA 3383(T) and M. shangrilense CCBAU 65327(T) were 41.1 %, 48.8 % and 23.4 %, respectively, clearly indicating that strain SCAU7(T) represents a novel species. A series of phenotypic and genotypic tests and comparison of cellular fatty acids indicated that the novel group of isolates was distinct from previously described species. Therefore, we propose that strains SCAU7(T) and SCAU27 represent a novel species of the genus Mesorhizobium, Mesorhizobium sangaii sp. nov., with strain SCAU7(T) (= HAMBI 3318(T) = ACCC 13218(T)) as the type strain.
authors: Department of Resources and Environment, Sichuan Agricultural University, Chengdu 611130, Sichuan, PR China.
authors: Shen
authors: S
authors: Zhou
authors: College of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621000, Sichuan, PR China.
authors: Qiongfang
authors: Q
authors: Li
authors: Department of Resources and Environment, Sichuan Agricultural University, Chengdu 611130, Sichuan, PR China.
authors: Huaming
authors: H
authors: Jiang
authors: Department of Applied Chemistry and Microbiology, University of Helsinki, Helsinki FIN-00014, Finland.
authors: Kristina
authors: K
authors: Lindström
authors: Department of Resources and Environment, Sichuan Agricultural University, Chengdu 611130, Sichuan, PR China.
authors: Xiaoping
authors: X
authors: Zhang
mesh_terms: D027883:Astragalus Plant / Q000382:microbiology*; D015373:Bacterial Typing Techniques; D002681:China; D004269:DNA, Bacterial / Q000235:genetics; D005227:Fatty Acids / Q000032:analysis; D005798:Genes, Bacterial; D059128:Mesorhizobium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation; D009693:Nucleic Acid Hybridization; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D053204:Root Nodules, Plant / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S