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Membrane lipid polyunsaturation mediated by FATTY ACID DESATURASE 2 ( FAD 2 ) is involved in endoplasmic reticulum stress tolerance in Arabidopsis thaliana
Author(s) -
Nguyen Van Cam,
Nakamura Yuki,
Kanehara Kazue
Publication year - 2019
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/tpj.14338
Subject(s) - endoplasmic reticulum , tunicamycin , unfolded protein response , arabidopsis , biochemistry , linoleic acid , fatty acid desaturase , arabidopsis thaliana , fatty acid , biology , mutant , polyunsaturated fatty acid , oleic acid , chemistry , microbiology and biotechnology , gene
Summary Unsaturation of membrane glycerolipid classes at their hydrophobic fatty acid tails critically affects the physical nature of the lipid molecule. In Arabidopsis thaliana , 7 fatty acid desaturases ( FAD s) differently desaturate each glycerolipid class in plastids and the endoplasmic reticulum ( ER ). Here, we showed that polyunsaturation of ER glycerolipids is required for the ER stress response. Through systematic screening of FAD mutants, we found that a mutant of FAD 2 resulted in a hypersensitive response to tunicamycin, a chemical inducer of ER stress. FAD 2 converts oleic acid to linoleic acid of the fatty acyl groups of ER ‐synthesized phospholipids. Our functional in vivo reporter assay revealed the ER localization and distinct tissue‐specific expression patterns of FAD 2. Moreover, glycerolipid profiling of both mutants and overexpressors of FAD 2 under tunicamycin‐induced ER stress conditions, along with phenotypic screening of the mutants of the FAD family, suggested that the ratio of monounsaturated fatty acids to polyunsaturated fatty acids, particularly 18:1 to 18:2 species, may be an important factor in allowing the ER membrane to cope with ER stress. Therefore, our results suggest that membrane lipid polyunsaturation mediated by FAD 2 is involved in ER stress tolerance in Arabidopsis .