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Research article - Peer-reviewed, 1999

Cytokinin production by Paenibacillus polymyxa

Timmusk, Salme; Nicander, Björn; Granhall, Ulf; Tillberg, Elisabeth


The production of hormones has been suggested to be one of the mechanisms by which plant growth-promoting rhizobacteria (PGPR) stimulate plant growth. To evaluate whether the free-living soil bacterium,Paenibacillus polymyxa, releases the hormone group cytokinins and, if so, their identity, the content of cytokinins in the growth media, before and after cultivation of this bacterium, was determined by immunoaffinity chromatography (IAC). This method allows the isolation of almost all known cytokinins and their metabolites. Separation and characterization were done by high performance liquid chromatography (HPLC) with on-line ultraviolet (UV) detection, and final identification was by gas chromatography-mass spectrometry.Iso-pentenyladenine (iP) was identified in the two defined media used for the cultivation ofP. polymyxa, but not earlier than at its late stationary growth. A third medium, supplemented with yeast extract, containediso-pentenyladenine riboside (iPR) and some additional cytokinin-like substances before inoculation. When the same medium was sampled after the cultivation ofP. polymyxaup to its logarithmic growth phase, the cytokinin concentration had decreased. After prolonged cultivation ofP. polymyxa, small amounts of iP appeared in all three media, and iPR had disappeared from the yeast-containing medium, which indicates that the bacterium can metabolize cytokinins.

Published in

Soil Biology and Biochemistry
1999, Volume: 31, number: 13, pages: 1847-1852
Publisher: Elsevier

    SLU Authors

    • Timmusk, Salme

      • Sveriges lantbruksuniversitet, Swedish University of Agricultural Sciences
      • Nicander, Björn

        • Sveriges lantbruksuniversitet, Swedish University of Agricultural Sciences
          • Tillberg, Elisabeth

            • Sveriges lantbruksuniversitet, Swedish University of Agricultural Sciences

          UKÄ Subject classification

          Plant Biotechnology

          Publication Identifiers


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