title: Genetic diversity of rhizobia associated with Vicia faba in three ecological regions of China.
abstract: Great genetic diversity was revealed among 75 rhizobal isolates associated with Vicia faba grown in Chinese fields with AFLP, ARDRA, 16S rDNA sequencing, DNA-DNA hybridization, BOX-PCR and RFLP of PCR-amplified nodD and nodC. Most of the isolates were Rhizobium leguminosarum, and six isolates belonged to an unnamed Rhizobium species. In the homogeneity analysis, the isolates were grouped into three clusters corresponding to (1) autumn sowing (subtropical) region where the winter ecotype of V. faba was cultivated, (2) spring sowing (temperate) region where the spring ecotype was grown, and (3) Yunnan province where the intermediate ecotype was sown either in spring or in autumn. Nonrandom associations were found among the nod genotypes, genomic types and ecological regions, indicating an epidemic symbiotic gene transfer pattern among different genomic backgrounds within an ecological region and a relatively limited transfer pattern between different regions. Conclusively, the present results suggested an endemic population structure of V. faba rhizobia in Chinese fields and demonstrated a novel rhizobium associated with faba bean.
authors.affiliation: Key Laboratory of Agro-Microbial Resource and Application, Ministry of Agriculture/College of Biological Sciences, China Agricultural University, 100094 Beijing, China.
authors.forename: Chang Fu
authors.initials: CF
authors.lastname: Tian
authors.forename: En Tao
authors.initials: ET
authors.lastname: Wang
authors.forename: Tian Xu
authors.initials: TX
authors.lastname: Han
authors.forename: Xin Hua
authors.initials: XH
authors.lastname: Sui
authors.forename: Wen Xin
authors.initials: WX
authors.lastname: Chen
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D002681:China; D017753:Ecosystem; D014644:Genetic Variation; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D012231:Rhizobium / Q000235:genetics* / Q000302:isolation & purification; D031307:Vicia faba / Q000254:growth & development / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; C060773:NodD protein, Bacteria