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Arabidopsis ACYL ‐ COA ‐ BINDING PROTEIN 1 interacts with STEROL C4‐ METHYL OXIDASE 1‐2 to modulate gene expression of homeodomain‐leucine zipper IV transcription factors
Author(s) -
Lung ShiuCheung,
Liao Pan,
Yeung Edward C.,
Hsiao AnShan,
Xue Yan,
Chye MeeLen
Publication year - 2018
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14965
Subject(s) - leucine zipper , sterol regulatory element binding protein , biology , transcription factor , biochemistry , microbiology and biotechnology , sterol , arabidopsis , basic helix loop helix leucine zipper transcription factors , gene , dna binding protein , mutant , cholesterol
Summary Fatty acids ( FA s) and sterols constitute building blocks of eukaryotic membranes and lipid signals. Co‐regulation of FA and sterol synthesis is mediated by sterol regulatory element‐binding proteins in animals but remains elusive in plants. We reported recently that Arabidopsis ACYL ‐ COA ‐ BINDING PROTEIN 1 ( ACBP 1) modulates sterol synthesis via protein–protein interaction with STEROL C4‐ METHYL OXIDASE 1‐1 ( SMO 1‐1). Herein, ACBP 1 was demonstrated to co‐express and interact with SMO 1‐2 by yeast two‐hybrid, co‐localization, pull‐down, co‐immunoprecipitation and β‐glucuronidase assays. SMO 1‐2 silenced in acbp1 was used in phenotyping, GC‐MS and expression profiling. ACBP 1 co‐expressed with SMO 1‐2 in embryo sacs, pollen and trichomes, corroborating with cooperative tissue‐specific functions unseen with SMO 1‐1. SMO 1‐2 silencing in acbp1 impaired seed development, male and female gamete transmission, and pollen function. Genes encoding homeodomain‐leucine zipper IV transcription factors ( HDG 5 , HDG 10 , HDG 11 and GLABRA 2 ), which potentially bind phospholipids/sterols, were transcribed aberrantly. GLABRA 2 targets ( MYB 23 , MUM 4 and PLD α 1 ) were misregulated, causing glabra2 ‐resembling trichome, seed coat mucilage and oil‐accumulating phenotypes. Together with altered sterol and FA compositions upon ACBP 1 mutation and/or SMO 1‐2 silencing, ACBP 1– SMO 1 interaction appears to mediate homeostatic co‐regulation of FA s and sterols, which serve as lipid modulators for gene expression of homeodomain‐leucine zipper IV transcription factors.