Biodiv Sci ›› 2010, Vol. 18 ›› Issue (2): 182-187.DOI: 10.3724/SP.J.1003.2010.195

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Diversity of IAA-producing endophytic bacteria isolated from the roots of Cymbidium goeringii

Lin Liu1; Lei Sun1*; Ruiying Zhang1; Na Yao2; Lubin Li2*   

  1. 1 College of Life Sciences, Hebei University, Key Laboratory of Microbial Diversity Research and Application of Hebei Province, Baoding, Hebei 071002

    2 Research Institute of Forestry, Chinese Academy of Forestry; Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Beijing 100091
  • Received:2009-09-15 Online:2010-03-20 Published:2010-03-20
  • Contact: Lei Sun

Abstract:

Endophytic bacteria can directly stimulate plant growth in several ways, including production of plant hormones such as indole-3-acetic acid (IAA). We investigated the diversity of IAA-producing endophytic bacteria in the roots of Cymbidium goeringii using culture-dependent approaches. A total of 57 IAA-producing strains were obtained from 256 strains isolated from the interior roots of C. goeringii. Based on amplified ribosomal DNA restriction analyses (ARDRA) and 16S rDNA sequences, these 57 strains were divided into 25 groups. The IAA-producing endophytic bacteria were grouped into six phyla, i.e., Alphaproteobacteria (35.1%), Firmicutes (33.3%), Gammaproteobacteria (14.0%), Betaproteobacteria (8.8%), Actinobacteria (7.0%) and Bacteroidetes (1.8%). The dominant groups were Alphaproteobacteria and Firmicutes, and the dominant genus, Paenibacillus, produced relatively high levels of IAA. In addition, four potential novel taxonomic units were found. Our results revealed diverse and abundant communities of IAA-producing endophytic bacteria in the roots of C. goeringii and highlight the microbial resources represented by plant growth-promoting bacteria.