Molecular Breeding

, Volume 9, Issue 2, pp 73–80 | Cite as

Overexpression of ornithine-δ-aminotransferase increases proline biosynthesis and confers osmotolerance in transgenic plants

  • Nancy H. Roosens
  • Fawaz Al Bitar
  • Kristof Loenders
  • Geert Angenon
  • Michel Jacobs


Accumulationof proline is a way to increase tolerance to water stress in plants. Therefore,considerable attention has been devoted to optimise proline biosynthesis intransgenic plants. Glutamate and ornithine are both precursors of proline butwhile genes of the glutamate pathway were overexpressed in transgenic plants,no gene encoding an enzyme of the ornithine pathway was considered until now. Thepresent study aims to establish if the overexpression ofornithine-δ-aminotransferase (δ-OAT) represents an additional wayto increase proline content. To achieve this goal, anArabidopsis δ-OAT cDNA was fused to the CaMV35Spromoter and introduced via Agrobacterium transformationinto Nicotiana plumbaginifolia. Overexpression of theδ-OAT cDNA in the analysed transgenic lines was linked to an increase inδ-OAT enzyme activity. The transgenic lines presenting high enzymaticactivity synthesized more proline than the control plants and showed a higherbiomass and a higher germination rate under osmotic stress conditions. Thesestudies reveal a new and efficient way to increase proline content in plantsand to enhance crop tolerance.

Ornithine-amino-transferase Osmotolerance Proline overproduction Transgenic plants 


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Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Nancy H. Roosens
    • 1
  • Fawaz Al Bitar
    • 2
  • Kristof Loenders
    • 1
  • Geert Angenon
    • 1
  • Michel Jacobs
    • 1
  1. 1.Laboratorium voor PlantengeneticaVrije Universiteit BrusselPaardenstraatBelgium
  2. 2.Laboratoire de Physiologie VégétaleUniversité Libre de BruxellesBrusselsBelgium

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