Biology and Fertility of Soils

, Volume 45, Issue 6, pp 669–674

A diazotrophic, indole-3-acetic acid-producing endophyte from wild cottonwood


  • Gang Xin
    • Department of Civil and Environmental EngineeringUniversity of Washington
    • Hydranautics
  • Gengyun Zhang
    • College of Forest ResourcesUniversity of Washington
  • Jun Won Kang
    • College of Forest ResourcesUniversity of Washington
  • James T. Staley
    • Department of MicrobiologyUniversity of Washington
    • College of Forest ResourcesUniversity of Washington
Short Communication

DOI: 10.1007/s00374-009-0377-8

Cite this article as:
Xin, G., Zhang, G., Kang, J.W. et al. Biol Fertil Soils (2009) 45: 669. doi:10.1007/s00374-009-0377-8


An endophytic bacterium, wild poplar strain B (WPB), isolated from stems of wild cottonwood (Populus trichocarpa) was identified to Burkholderia vietnamiensis by analyzing the recA and rDNA genes. Phylogenetic analysis of the nifHDK cluster indicates that the WPB isolate shares high sequence similarity with known B. vietnamiensis strains. The nitrogenase activity of WPB was determined by a 15N2 incorporation assay and an acetylene reduction assay. WPB was also monitored for production of indole-3-acetic acid (IAA), a phytohormone which can promote plant growth, when incubated with l-tryptophan. In addition, its plant growth promotion capacity was assessed by inoculating the WPB strain onto Kentucky bluegrass in nitrogen-free medium. Compared to uninoculated control plants, the plants inoculated with WPB gained more dry weight (42%, p = 0.01) and more nitrogen content (37%, p = 0.04) in 50 days.


Diazotrophic endophyte Poplar trees Plant growth promotion Burkholderia vietnamiensis IAA Phylogenetic analysis Turf grass Nitrogen fixation Populus Auxin Endophytes

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© Springer-Verlag 2009