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Current Microbiology

, Volume 32, Issue 2, pp 67–71 | Cite as

Isolation and Characterization of Mutants of the Plant Growth-Promoting Rhizobacterium Pseudomonas putida GR12-2 That Overproduce Indoleacetic Acid

  • Hong  Xie
  • J.J.  Pasternak
  • Bernard R.  Glick

Abstract.

Following transposon Tn5 mutagenesis of the plant growth-promoting rhizobacterium Pseudomonas putida GR12-2, mutants that were able to grow in the presence of the tryptophan analog 5-fluorotryptophan were selected. Seven of the 50 5-fluorotryptophan-resistant mutants overproduced the phytohormone indoleacetic acid (IAA). Of these seven mutants, the highest level of IAA was observed with strain P. putida GR12-2/aux1, which produced four times the amount of indoleacetic acid synthesized by the wild-type strain. Strain P. putida GR12-2/aux1, in contrast to the wild type, lost the ability to stimulate the elongation of the roots of canola seedlings under gnotobiotic conditions. The growth rate, siderophore production, and 1-aminocyclopropane-1-carboxylate deaminase activity of mutant strain P. putida GR12-2/aux1 were identical to those of the wild-type strain. The role of IAA in the mechanism of plant growth stimulation by P. putida GR12-2 and other plant growth-promoting rhizobacteria is discussed.

Keywords

Growth Rate Plant Growth Pseudomonas Tryptophan Mutant Strain 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag New York Inc. 1996

Authors and Affiliations

  • Hong  Xie
    • 1
  • J.J.  Pasternak
    • 1
  • Bernard R.  Glick
    • 1
  1. 1.Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 CA

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