The Peptaibol Alamethicin Induces an rRNA-Cleavage-Associated Death in Arabidopsis thaliana

Authors

  • Sonia Rippa,

    1. Université de Technologie de Compiègne, CNRS, UMR 6022 Génie Enzymatique et Cellulaire, BP 20529, F-60205 Compiègne Cedex, (phone: +33 5 5712 2366; fax: +33 5 5712 2369)
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  • Hervé Adenier,

    1. Université de Technologie de Compiègne, CNRS, UMR 6022 Génie Enzymatique et Cellulaire, BP 20529, F-60205 Compiègne Cedex, (phone: +33 5 5712 2366; fax: +33 5 5712 2369)
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  • Michel Derbaly,

    1. Université de Technologie de Compiègne, CNRS, UMR 6022 Génie Enzymatique et Cellulaire, BP 20529, F-60205 Compiègne Cedex, (phone: +33 5 5712 2366; fax: +33 5 5712 2369)
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  • Laure Béven

    1. Université de Technologie de Compiègne, CNRS, UMR 6022 Génie Enzymatique et Cellulaire, BP 20529, F-60205 Compiègne Cedex, (phone: +33 5 5712 2366; fax: +33 5 5712 2369)
    2. Present address: Université de Bordeaux 2, INRA, UMR 1090 Génomique Diversité Pouvoir Pathogène, F-33883 Villenave d'Ornon Cedex.
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Abstract

The plant-metabolic response to amphipathic peptides produced by the soil fungi of the genus Trichoderma remains largely unknown. The present investigation was undertaken to examine the death process in alamethicin-treated Arabidopsis thaliana plantlets. The rapid death triggered by alamethicin (at 50 μM) was shown to be associated with protein-synthesis arrest and with specific cleavage of 18S and 25S ribosomal RNA. The use of an inhibitor of nitric oxide (NO) synthases and of an NO scavenger suggested that rRNA cleavage was suppressed by NO. Experiments conducted with a synthetic alamethicin analogue, in which all α-aminoisobutyric acid (Aib) residues have been replaced by leucine moieties, showed that the non-coded residues are essential for the ability of the peptaibol to induce rRNA cleavage in Arabidopsis. Our data indicate that further investigations on the mode of action of alamethicin in planta could be of great interest to study the death-signaling pathway associated with rRNA degradation in plants.

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