Molecular and General Genetics MGG

, Volume 256, Issue 3, pp 211–222 | Cite as

Differential activation of two ACC oxidase gene promoters from melon during plant development and in response to pathogen attack

  • E. Lasserre
  • F. Godard
  • T. Bouquin
  • J. A. Hernandez
  • J.-C. Pech
  • D. Roby
  • C. Balagué
ORIGINAL PAPER

Abstract

ACC (1-aminocyclopropane-1-carboxylate) oxidase genes are differentially expressed in melon during development and in response to various stresses. We investigated the molecular basis of their transcription by analyzing the 5′ untranslated regions of the ACC oxidase genes CM-ACO1 and CM-ACO3. In order to determine how their temporal and spatial expression patterns were established, we fused the promoter regions of CM-ACO1 (726 bp) and CM-ACO3 (2260 bp) to the β-glucuronidase (GUS) reporter gene and examined their regulation in transgenic tobacco plants. The CM-ACO1 promoter was able to drive GUS expression in response to wounding, and to treatment with ethylene or copper sulfate. It was also rapidly induced (8–12 h post-inoculation) in tobacco leaves inoculated with the hypersensitive response (HR)-inducing bacterium Ralstonia solanacearum. Expression was also observed during compatible interactions but was delayed. In contrast, the CM-ACO3 promoter was not expressed in response to infection, but was up-regulated during flower development. Both promoters were regulated during leaf senescence but in different patterns. The CM-ACO1-driven GUS activity increased sharply concomitantly with the onset of chlorophyll breakdown, while the CM-ACO3 promoter drove strong GUS expression in green, fully expanded leaves and this declined at the onset of senescence. This result is consistent with the expression patterns of these two genes in senescent melon leaves. These data suggest that the regulation of expression of CM-ACO1 is related preferentially to stress responses, whereas CM-ACO3 seems to be associated with developmental processes. The possible role of ethylene is discussed, particularly in the regulation of the CM-ACO1 gene in response to stress and during senescence.

Key words ACC oxidase Ethylene Hypersensitive Response Senescence Transcriptional activation 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • E. Lasserre
    • 1
  • F. Godard
    • 2
  • T. Bouquin
    • 1
  • J. A. Hernandez
    • 1
  • J.-C. Pech
    • 1
  • D. Roby
    • 2
  • C. Balagué
    • 1
  1. 1.Laboratoire Ethylène et Mécanismes Moléculaires de la Maturation des Fruits UA-INRA, Ecole Nationale Supérieure Agronomique de Toulouse, 145 Avenue de Muret, 31076 Toulouse Cedex, France Fax: +33-5-6213-6541. e-mail: balague@ensat.frFR
  2. 2.Laboratoire de Biologie Moléculaire des Relations Plantes/Microorganismes, UMR CNRS/ INRA 215, BP27 31326 Castanet-Tolosan Cedex, FranceFR

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