title: Characterization of Astragalus sinicus rhizobia by restriction fragment length polymorphism analysis of chromosomal and nodulation genes regions.
abstract: Two hundred and four isolates of rhizobia were sampled from root nodules of Astragalus sinicus grown in rice fields of six southern provinces of China. Genotypic diversity was determined by Southern hybridization using nodDBC genes as a probe, restriction fragment length polymorphism (RFLP) analysis of PCR-amplified 16S-23S rDNA intergenic spacers (IGS), and plasmid profile. Our results show that rhizobia associated with A. sinicus were very diverse, and 10 genotypes were resolved within the previously identified dominant 16S rDNA type. Diversity levels varied greatly between different geographical locations. The same nod gene genotypes were harbored by distinct chromosomal types, suggesting that lateral plasmid transfer occurred during the evolution process.
authors.affiliation: Department of Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070 P.R. China.
authors.forename: X W
authors.initials: XW
authors.lastname: Guo
authors.forename: X X
authors.initials: XX
authors.lastname: Zhang
authors.forename: Z M
authors.initials: ZM
authors.lastname: Zhang
authors.forename: F D
authors.initials: FD
authors.lastname: Li
mesh_terms: D015139:Blotting, Southern; D005798:Genes, Bacterial; D014644:Genetic Variation; D018517:Plant Roots / Q000382:microbiology*; D010944:Plants / Q000382:microbiology*; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D012230:Rhizobiaceae / Q000235:genetics* / Q000502:physiology
chemical_list: D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S