title: AtDSEL, an Arabidopsis cytosolic DAD1-like acylhydrolase, is involved in negative regulation of storage oil mobilization during seedling establishment.
abstract: Mobilization of seed storage reserves is essential for seed germination and seedling establishment. Here, we report that AtDSEL, an Arabidopsis thalianaDAD1-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.
authors.affiliation: Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea.
authors.forename: Eun Yu
authors.initials: EY
authors.lastname: Kim
authors.forename: Young Sam
authors.initials: YS
authors.lastname: Seo
authors.forename: Woo Taek
authors.initials: WT
authors.lastname: Kim
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018548:Cotyledon / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D035264:Flowers / Q000201:enzymology / Q000235:genetics; D015870:Gene Expression; D018525:Germination; D008049:Lipase / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D015388:Organelles / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D010084:Oxidation-Reduction; D010641:Phenotype; D054466:Phospholipases A1 / Q000235:genetics; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics; D010938:Plant Oils / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D018547:Plant Stems / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D012639:Seeds / Q000254:growth & development / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D010938:Plant Oils; D011993:Recombinant Fusion Proteins; D015084:2,4-Dichlorophenoxyacetic Acid; C580596:DSEL protein, Arabidopsis; D008049:Lipase; C445094:DAD1 protein, Arabidopsis; D054466:Phospholipases A1; C004764:4-(2,4-dichlorophenoxy)butyric acid