title: Rhizobium helianthi sp. nov., isolated from the rhizosphere of sunflower.
abstract: A Gram-stain-negative, non-spore-forming, rod-shaped and aerobic bacterium, designated Xi19T, was isolated from a soil sample collected from the rhizosphere of sunflower (Helianthus annuus) in Wuyuan county of Inner Mongolia, China and was characterized taxonomically by using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel isolate was related to species of the genus Rhizobium, sharing the greatest 16S rRNA gene sequence similarity with Rhizobium rhizoryzae J3-AN59T (98.4 %), followed by Rhizobium pseudoryzae J3-A127T (97.4 %). There were low similarities ( < 91 %) between the atpD, recA and glnII gene sequences of the novel strain and those of members of the genus Rhizobium. DNA-DNA hybridization values between strain Xi19T and the most related strain Rhizobium rhizoryzae J3-AN59T were low. The major cellular fatty acids of strain Xi19T were C16 : 0, summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C19 : 0 cyclo ω8c. Q-10 was identified as the predominant ubiquinone and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine. The DNA G+C content of strain Xi19T was 60.2 mol%. On the basis of physiological and biochemical characteristics, coupled with genotypic data obtained in this work, strain Xi19T represents a novel species of the genus Rhizobium, for which the name Rhizobium helianthi is proposed. The type strain is Xi19T ( = CGMCC 1.12192T = KCTC 23879T).
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing 100081, PR China.
authors.forename: Xuexin
authors.initials: X
authors.lastname: Wei
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing 100081, PR China.
authors.forename: Shouwei
authors.initials: S
authors.lastname: Yan
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing 100081, PR China.
authors.forename: Dai
authors.initials: D
authors.lastname: Li
authors.affiliation: Institute of Agri-resources and Regional Planning, CAAS, Beijing 100081, PR China.
authors.forename: Huancheng
authors.initials: H
authors.lastname: Pang
authors.affiliation: Institute of Agri-resources and Regional Planning, CAAS, Beijing 100081, PR China.
authors.forename: Yuyi
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing 100081, PR China.
authors.forename: Jianli
authors.initials: J
authors.lastname: Zhang
mesh_terms: D015373:Bacterial Typing Techniques; D001482:Base Composition; D002681:China; D004269:DNA, Bacterial / Q000235:genetics; D005227:Fatty Acids / Q000737:chemistry; D006368:Helianthus / Q000382:microbiology*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010743:Phospholipids / Q000737:chemistry; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012231:Rhizobium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D058441:Rhizosphere; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D004269:DNA, Bacterial; D005227:Fatty Acids; D010743:Phospholipids; D012336:RNA, Ribosomal, 16S; D014451:Ubiquinone; C024989:coenzyme Q10