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Identification of the Arabidopsis dry2/sqe1‐5 mutant reveals a central role for sterols in drought tolerance and regulation of reactive oxygen species
Author(s) -
Posé David,
Castanedo Itziar,
Borsani Omar,
Nieto Benjamín,
Rosado Abel,
Taconnat Ludivine,
Ferrer Albert,
Dolan Liam,
Valpuesta Victoriano,
Botella Miguel A.
Publication year - 2009
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2009.03849.x
Subject(s) - sterol , squalene monooxygenase , mutant , reactive oxygen species , squalene , arabidopsis , biochemistry , biology , oxidase test , arabidopsis thaliana , nadph oxidase , biosynthesis , microbiology and biotechnology , botany , chemistry , enzyme , gene , cholesterol
Summary 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.