AtDSEL, an Arabidopsis cytosolic DAD1-like acylhydrolase, is involved in negative regulation of storage oil mobilization during seedling establishment

• Published in: Journal of plant physiology Vol. 168; no. 14; pp. 1705 - 1709
• Main Authors: Kim, Eun Yu, Seo, Young Sam, Kim, Woo Taek
• Format: Journal Article
• Language: English
• Published: Munich Elsevier GmbH 15.09.2011; Elsevier
• Subjects: 2,4-DB; 2,4-Dichlorophenoxyacetic Acid - analogs & derivatives; 2,4-Dichlorophenoxyacetic Acid - pharmacology; Arabidopsis; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - ultrastructure; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Bacteria; Biological and medical sciences; Carbon; Control; Cotyledon - genetics; Cotyledon - growth & development; Cotyledon - ultrastructure; cotyledons; culture media; DAD1-like acylhydrolase; electron microscopy; Fatty acids; Flowers - enzymology; Flowers - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression; gene overexpression; Germination; Lipase; Lipase - genetics; Lipase - metabolism; lipid bodies; Mutation; Oil breakdown; oils; Organelles - enzymology; Organelles - metabolism; Organelles - ultrastructure; Oxidation-Reduction; peroxisomes; Phenotype; Phospholipases A1 - genetics; Plant Leaves - enzymology; Plant Leaves - genetics; Plant Oils - metabolism; Plant physiology and development; Plant Roots - enzymology; Plant Roots - genetics; Plant Roots - growth & development; Plant Stems - enzymology; Plant Stems - genetics; Plant Stems - growth & development; Plants, Genetically Modified; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; seed germination; seed storage; Seedling establishment; seedling growth; seedlings; Seedlings - enzymology; Seedlings - genetics; Seedlings - growth & development; Seedlings - ultrastructure; Seeds; Seeds - growth & development; Seeds - metabolism; Storage oil; Sucrose; triacylglycerol lipase; Seedling establishment; 2,4-D; 2,4-DB; DAG; 1-LPC; DAD1-like acylhydrolase; Oil breakdown; GFP; MAG; PC; Storage oil; DGDG; MGDG; TAG; Plant juvenile growth stage; Cytosol; Arabidopsis thaliana; Mobilization; Storage; Plant physiology; Cruciferae; Dicotyledones; Angiospermae; Spermatophyta; Experimental plant
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/j.jplph.2011.03.004

Mobilization of seed storage reserves is essential for seed germination and seedling establishment. Here, we report that AtDSEL, an Arabidopsis thaliana DAD1-like Seedling Establishment-related Lipase, is involved in the mobilization of storage oils for early seedling establishment. AtDSEL is a cytosolic member of the DAD1-like acylhydrolase family encoded by At4g18550. Bacterially expressed AtDSEL preferentially hydrolyzed 1,3-diacylglycerol and 1-monoacylglycerol, suggesting that AtDSEL is an sn-1-specific lipase. AtDSEL-overexpressing transgenic Arabidopsis plants ( 35S:AtDSEL) were defective in post-germinative seedling growth in medium without an exogenous carbon source. This phenotype was rescued by the addition of sucrose to the growth medium. In contrast, loss-of-function mutant plants ( atdsel-1 and atdsel-2) had a mildly fast-growing phenotype regardless of the presence of an exogenous carbon source. Electron microscopy revealed that 5-day-old 35S:AtDSEL cotyledons retained numerous peroxisomes and oil bodies, which were exhausted in wild-type and mutant cotyledons. The impaired seedling establishment of 35S:AtDSEL was not rescued by the addition of an exogenous fatty acid source, and 35S:AtDSEL seedling growth was insensitive to 2,4-dichlorophenoxybutyric acid, indicating that β-oxidation was blocked in AtDSEL-overexpressers. These results suggest that AtDSEL is involved in the negative regulation of seedling establishment by inhibiting the breakdown of storage oils.