Identification of the Arabidopsis dry2/sqe1-5 mutant reveals a central role for sterols in drought tolerance and regulation of reactive oxygen species.

Journal article

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.

Authors: Posé, D; Castanedo, I; Borsani, O; Nieto, B; Rosado, A

• Publication status: Published
• Journal: Plant journal : for cell and molecular biology
• Volume: 59
• Issue: 1
• Pages: 63-76
• Publication date: 2009-07-01
• DOI: 10.1111/j.1365-313x.2009.03849.x
• EISSN: 1365-313X
• ISSN: 0960-7412
• Language: English
• Keywords: Gene Expression Regulation, Plant; Sterols; Genetic Complementation Test; DNA, Plant; Stress, Physiological; Mutation; Plant Roots; Arabidopsis; Plant Stomata; NADPH Oxidase; Reactive Oxygen Species; Squalene Monooxygenase; Dehydration; Arabidopsis Proteins; Droughts; Oligonucleotide Array Sequence Analysis