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Journal of Plant Growth Regulation

, Volume 18, Issue 2, pp 73–79 | Cite as

The Herbicidally Active Compound N-2-(6-Methyl-Pyridyl)-Aminomethylene Bisphosphonic Acid Inhibits In Vivo Aromatic Biosynthesis

  • G.  Forlani
  • B.  Lejczak
  • P.  Kafarski

Abstract.

The effect of N-2-(6-methyl-pyridyl)-aminomethylene bisphosphonic acid (M-pyr-AMBPA), a compound previously shown to exhibit herbicidal properties on whole plants and to inhibit in vitro activity of the first enzyme in the shikimate pathway, 3-deoxy-d-arabino-heptulosonate-7-phosphate (DAHP) synthase, was investigated on Nicotiana plumbaginifolia suspension cultured cells and compared to that of the herbicide glyphosate. The addition of M-pyr-AMBPA from 10−4 to 10−3 M was found to cause a severe cell growth reduction. Kinetic analysis of partially purified DAHP synthase accounted for non-competitive inhibition type with respect to both phospho-enol-pyruvate and erythrose-4-phosphate, with KI values of 0.43 and 0.62 mM, respectively. Amino acid pool measurements of cells grown in the presence of sublethal doses of M-pyr-AMBPA pointed to an actual reduction of free aromatic amino acids, showing that DAHP synthase inhibition takes place in vivo, and suggesting that the interference of this aminophosphonate with plant aromatic biosynthesis may account for a large part of its phytotoxicity. However, exogenous supply of a mixture of phenylalanine, tyrosine and tryptophan failed to achieve full reversal of cell growth inhibition, yet the occurrence of other target(s) cannot be ruled out.

Key Words.N-2-(6-methyl-pyridyl)-aminomethylene bisphosphonic acid—Amino acid biosynthesis inhibitors—DAHP synthase—Glyphosate—Aromatic metabolism 

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Copyright information

© Springer-Verlag New York Inc. 1999

Authors and Affiliations

  • G.  Forlani
    • 1
  • B.  Lejczak
    • 2
  • P.  Kafarski
    • 2
  1. 1.Department of Genetics and Microbiology, University of Pavia, 27100 Pavia, ItalyIT
  2. 2.Institute of Organic Chemistry, Biochemistry and Biotechnology, Wroclaw University of Technology, 50-370 Wroclaw, PolandPL

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