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

• Published in: The New phytologist Vol. 184; no. 4; pp. 885 - 897
• Main Authors: Müller, Kerstin, Carstens, Anna Catharina, Linkies, Ada, Torres, Miguel Angel, Leubner-Metzger, Gerhard
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.12.2009; Blackwell Publishing; Blackwell Publishing Ltd
• Subjects: Abscisic Acid; abscisic acid (ABA); After ripening; alternative splicing; Arabidopsis - genetics; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; cress (Lepidium sativum); Dormancy; Embryos; Endosperm; Gene Expression; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; Germination; Germination - genetics; Germination - physiology; Introns; Lepidium - genetics; Lepidium - physiology; Mutation; NADPH Oxidases - genetics; NADPH Oxidases - metabolism; NADPH-oxidase (Rboh); Onium Compounds; Plants; Protein Carbonylation; Reactive Oxygen Species; RNA, Messenger; seed dormancy; Seed germination; Seeds; Seeds - genetics; Seeds - physiology; Superoxides
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2009.03005.x

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.