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The NADPH-oxidase AtrbohB plays a role in Arabidopsis seed after-ripening

Authors

  • Kerstin Müller,

    1. Faculty of Biology, Institute for Biology II, Botany/Plant Physiology, University of Freiburg, Schänzlestr. 1, D–79104 Freiburg, Germany
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  • Anna Catharina Carstens,

    1. Faculty of Biology, Institute for Biology II, Botany/Plant Physiology, University of Freiburg, Schänzlestr. 1, D–79104 Freiburg, Germany
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  • Ada Linkies,

    1. Faculty of Biology, Institute for Biology II, Botany/Plant Physiology, University of Freiburg, Schänzlestr. 1, D–79104 Freiburg, Germany
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  • Miguel Angel Torres,

    1. Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, ES–28223 Pozuelo de Alarcón, Madrid, Spain
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  • Gerhard Leubner-Metzger

    1. Faculty of Biology, Institute for Biology II, Botany/Plant Physiology, University of Freiburg, Schänzlestr. 1, D–79104 Freiburg, Germany
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Author for correspondence:
Gerhard Leubner-Metzger
Tel: +49 761 2032936
Email: gerhard.leubner@biologie.uni-freiburg.de

Summary

  • Seeds can enter a state of dormancy, in which they do not germinate under optimal environmental conditions. Dormancy can be broken during seed after-ripening in the low-hydrated state.
  • By screening enhancer trap lines of Arabidopsis, we identified a role for the NADPH-oxidase AtrbohB in after-ripening. Semiquantitative PCR was used to investigate AtrbohB transcripts in seeds. These methods were complemented with a pharmacological approach using the inhibitor diphenylene iodonium chloride (DPI) and biomechanical measurements in the Brassicaceae seed model system cress (Lepidium sativum) as well as protein carbonylation assays.
  • atrbohB mutants fail to after-ripen and show reduced protein oxidation. AtrbohB pre-mRNA is alternatively spliced in seeds in a hormonally and developmentally regulated manner. AtrbohB is a major producer of superoxide in germinating Arabidopsis seeds, and inhibition of superoxide production by diphenylene iodonium (DPI) leads to a delay in Arabidopsis and cress seed germination and cress endosperm weakening.
  • Reactive oxygen species produced by AtrbohB during after-ripening could act via abscisic acid (ABA) signalling or post-translational protein modifications. Alternative splicing could be a general mechanism in after-ripening: by altered processing of stored pre-mRNAs seeds could react quickly to environmental changes.

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