title: Identification of the Arabidopsis dry2/sqe1-5 mutant reveals a central role for sterols in drought tolerance and regulation of reactive oxygen species.
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.
authors.affiliation: Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, 29071 Málaga, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Posé
authors.forename: Itziar
authors.initials: I
authors.lastname: Castanedo
authors.forename: Omar
authors.initials: O
authors.lastname: Borsani
authors.forename: Benjamín
authors.initials: B
authors.lastname: Nieto
authors.forename: Abel
authors.initials: A
authors.lastname: Rosado
authors.forename: Ludivine
authors.initials: L
authors.lastname: Taconnat
authors.forename: Albert
authors.initials: A
authors.lastname: Ferrer
authors.forename: Liam
authors.initials: L
authors.lastname: Dolan
authors.forename: Victoriano
authors.initials: V
authors.lastname: Valpuesta
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Botella
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018744:DNA, Plant / Q000235:genetics; D003681:Dehydration; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D009154:Mutation; D019255:NADPH Oxidases / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics; D054046:Plant Stomata / Q000201:enzymology / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism*; D050603:Squalene Monooxygenase / Q000235:genetics / Q000378:metabolism*; D013261:Sterols / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D017382:Reactive Oxygen Species; D013261:Sterols; D050603:Squalene Monooxygenase; D019255:NADPH Oxidases