Unregulated Sphingolipid Biosynthesis in Gene-Edited Arabidopsis ORM Mutants Results in Nonviable Seeds with Strongly Reduced Oil Content
| Autor: | Ariadna González-Solís, Jonathan E. Markham, Rebecca E. Cahoon, Teresa M. Dunn, Gongshe Han, Edgar B. Cahoon, Lu Gan, Yunfeng Li |
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| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
0301 basic medicine Saccharomyces cerevisiae Mutant Arabidopsis Plant Development Plant Science Genes Plant Models Biological 01 natural sciences 03 medical and health sciences Gene Expression Regulation Plant Gene expression Plant Oils Arabidopsis thaliana Research Articles Gene Editing Sphingolipids Base Sequence biology Arabidopsis Proteins Serine C-palmitoyltransferase Membrane Proteins Cell Biology biology.organism_classification Sphingolipid Up-Regulation Cell biology Transmembrane domain Phenotype 030104 developmental biology Seedlings Mutation Seeds Protein Binding Subcellular Fractions 010606 plant biology & botany |
| Zdroj: | Plant Cell |
| ISSN: | 1532-298X 1040-4651 |
| Popis: | Orosomucoid-like proteins (ORMs) interact with serine palmitoyltransferase (SPT) to negatively regulate sphingolipid biosynthesis, a reversible process critical for balancing the intracellular sphingolipid levels needed for growth and programmed cell death. Here, we show that ORM1 and ORM2 are essential for life cycle completion in Arabidopsis (Arabidopsis thaliana). Seeds from orm1 -/- orm2 -/- mutants, generated by crossing CRISPR/Cas9 knockout mutants for each gene, accumulated high levels of ceramide, indicative of unregulated sphingolipid biosynthesis. orm1 -/- orm2 -/- seeds were nonviable, displayed aberrant embryo development, and had >80% reduced oil content versus wild-type seeds. This phenotype was mimicked in Arabidopsis seeds expressing the SPT subunit LCB1 lacking its first transmembrane domain, which is critical for ORM-mediated regulation of SPT. We identified a mutant for ORM1 lacking one amino acid (Met-51) near its second transmembrane domain that retained its membrane topology. Expressing this allele in the orm2 background yielded plants that did not advance beyond the seedling stage, hyperaccumulated ceramides, and showed altered organellar structures and increased senescence- and pathogenesis-related gene expression. These seedlings also showed upregulated expression of genes for sphingolipid catabolic enzymes, pointing to additional mechanisms for maintaining sphingolipid homeostasis. ORM1 lacking Met-51 had strongly impaired interactions with LCB1 in a yeast (Saccharomyces cerevisiae) model, providing structural clues about regulatory interactions between ORM and SPT. |
| Databáze: | OpenAIRE |
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