Amino Acids

, Volume 30, Issue 2, pp 195–204

Herbicidal inhibitors of amino acid biosynthesis and herbicide-tolerant crops

  • S. Tan
  • R. Evans
  • B. Singh
Review Article

DOI: 10.1007/s00726-005-0254-1

Cite this article as:
Tan, S., Evans, R. & Singh, B. Amino Acids (2006) 30: 195. doi:10.1007/s00726-005-0254-1


Acetohydroxyacid synthase (AHAS) inhibitors interfere with branched-chain amino acid biosynthesis by inhibiting AHAS. Glyphosate affects aromatic amino acid biosynthesis by inhibiting 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Glufosinate inhibits glutamine synthetase and blocks biosynthesis of glutamine. AHAS gene variants that confer tolerance to AHAS inhibitors have been discovered in plants through selection or mutagenesis. Imidazolinone-tolerant crops have been commercialized based on these AHAS gene variants. A modified maize EPSPS gene and CP4-EPSPS gene from Agrobacterium sp. have been used to transform plants for target-based tolerance to glyphosate. A gox gene isolated from Ochrobactrum anthropi has also been employed to encode glyphosate oxidoreductase to detoxify glyphosate in plants. Glyphosate-tolerant crops with EPSPS transgene alone or both EPSPS and gox transgenes have been commercialized. Similarly, bar and pat genes isolated from Streptomyces hygroscopicus and S. viridochromogenes, respectively, have been inserted into plants to encode phosphinothricin N-acetyltransferase to detoxify glufosinate. Glufosinate-tolerant crops have been commercialized using one of these two transgenes.

Keywords: Acetohydroxyacid synthase – Acetolactate synthase – 5-Enolpyruvylshikimate-3-phosphate synthase – Imidazolinone – Glyphosate – Glufosinate – Herbicide tolerance 



acetohydroxyacid synthase


aminomethylphosphonic acid




5-enolpyruvylshikimate-3-phosphate synthase


glyphosate oxidoreductase


glutamine synthetase


phosphinothricin N-acetyltransferase

Copyright information

© Springer-Verlag/Wien 2006

Authors and Affiliations

  • S. Tan
    • 1
  • R. Evans
    • 1
  • B. Singh
    • 1
  1. 1.BASF Corporation, Research Triangle ParkNorth CarolinaU.S.A.

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