Genetic diversity of nodulating and non-nodulating rhizobia associated with wild soybean (Glycine soja Sieb. & Zucc.) in different ecoregions of China

Authors

  • Li Juan Wu,

    1. State Key Laboratory of Agro-Biotechnology, Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing, China
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  • Hai Qing Wang,

    1. State Key Laboratory of Agro-Biotechnology, Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing, China
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  • En Tao Wang,

    1. Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México D.F., México
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  • Wen Xin Chen,

    1. State Key Laboratory of Agro-Biotechnology, Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing, China
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  • Chang Fu Tian

    1. State Key Laboratory of Agro-Biotechnology, Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing, China
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  • Editor: Kornelia Smalla

Correspondence: Wen Xin Chen, State Key Laboratory of Agro-Biotechnology, Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing 100193, China. Tel./fax: +86 10 6273 4008; e-mail: wenxin@cau.edu.cn

Abstract

A total of 99 bacterial isolates that originated from root nodules of Glycine soja were characterized with restriction analyses of amplified 16S ribosomal DNA and 16S–23S rDNA intergenic spacers (ITS), and sequence analyses of 16S rRNA, rpoB, atpD, recA and nodC genes. When tested for nodulation of G. soja, 72 of the isolates were effective symbionts, and these belonged to five species: Bradyrhizobium japonicum, Bradyrhizobium elkanii, Bradyrhizobium yuanmingense, Bradyrhizobium liaoningense and Sinorhizobium fredii. All of these, except some B. yuanmingense strains, also formed effective nodules on the domesticated soybean Glycine max. The remaining 27 isolates did not nodulate either host, but were identified as Rhizobium. Phylogeny nodC in the G. soja symbionts suggested that this symbiosis gene was mainly maintained by vertical gene transfer. Different nodC sublineages and rrs-ITS clusters reflected the geographic origins of isolates in this study.

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