Identification of the Arabidopsis dry2/sqe1‐5 mutant reveals a central role for sterols in drought tolerance and regulation of reactive oxygen species |
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| Authors: | David Posé Itziar Castanedo Omar Borsani Benjamín Nieto Abel Rosado Ludivine Taconnat Albert Ferrer Liam Dolan Victoriano Valpuesta Miguel A. Botella |
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| Affiliation: | 1. Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, 29071 Málaga, Spain;2. Departamento de Biología Vegetal, Laboratorio de Bioquímica, Facultad de Agronomía, Avda. Garzón 780, 12900 Montevideo, Uruguay;3. Departament de Bioquímica i Biologia Molecular, Facultat de Farmàcia, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain;4. Present address: Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, Center for Plant Cell Biology, University of California, Riverside, CA 92521, USA.;5. INRA, Unite Mixte de Recherche en Genomique Vegetale, F‐91057 Evry, France;6. Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK |
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| Abstract: | Squalene epoxidase enzymes catalyse the conversion of squalene into 2,3‐oxidosqualene, the precursor of cyclic triterpenoids. Here we report that the Arabidopsis drought hypersensitive/squalene epoxidase 1‐5 (dry2/sqe1‐5) mutant, identified by its extreme hypersensitivity to drought stress, has altered stomatal responses and root defects because of a point mutation in the SQUALENE EPOXIDASE 1 (SQE1) gene. GC‐MS analysis indicated that the dry2/sqe1‐5 mutant has altered sterol composition in roots but wild‐type sterol composition in shoots, indicating an essential role for SQE1 in root sterol biosynthesis. Importantly, the stomatal and root defects of the dry2/sqe1‐5 mutant are associated with altered production of reactive oxygen species. As RHD2 NADPH oxidase is de‐localized in dry2/sqe1‐5 root hairs, we propose that sterols play an essential role in the localization of NADPH oxidases required for regulation of reactive oxygen species, stomatal responses and drought tolerance. |
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| Keywords: | squalene epoxidase sterol biosynthesis drought tolerance NADPH oxidase reactive oxygen species |
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