Abstract
Fatty acids (FAs) 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 PROTEIN1 (ACBP1) modulates sterol synthesis via protein–protein interaction with STEROL C4-METHYL OXIDASE1-1 (SMO1-1). Herein, ACBP1 was demonstrated to co-express and interact with SMO1-2 by yeast two-hybrid, co-localization, pull-down, co-immunoprecipitation and β-glucuronidase assays. SMO1-2 silenced in acbp1 was used in phenotyping, GC-MS and expression profiling. ACBP1 co-expressed with SMO1-2 in embryo sacs, pollen and trichomes, corroborating with cooperative tissue-specific functions unseen with SMO1-1. SMO1-2 silencing in acbp1 impaired seed development, male and female gamete transmission, and pollen function. Genes encoding homeodomain-leucine zipper IV transcription factors (HDG5, HDG10, HDG11 and GLABRA2), which potentially bind phospholipids/sterols, were transcribed aberrantly. GLABRA2 targets (MYB23, MUM4 and PLDα1) were misregulated, causing glabra2-resembling trichome, seed coat mucilage and oil-accumulating phenotypes. Together with altered sterol and FA compositions upon ACBP1 mutation and/or SMO1-2 silencing, ACBP1–SMO1 interaction appears to mediate homeostatic co-regulation of FAs and sterols, which serve as lipid modulators for gene expression of homeodomain-leucine zipper IV transcription factors.
Original language | English |
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Pages (from-to) | 183-200 |
Number of pages | 18 |
Journal | New Phytologist |
Volume | 218 |
Issue number | 1 |
DOIs | |
Publication status | Published - Apr 2018 |
Scopus Subject Areas
- Physiology
- Plant Science
User-Defined Keywords
- embryogenesis
- fatty acid
- GLABRA2
- lipid signaling
- protein interactor
- second messenger
- sterol
- trichome