title: Two novel diacylglycerol acyltransferase genes from Xanthoceras sorbifolia are responsible for its seed oil content.
abstract: Xanthoceras sorbifolia is an excellent model system for studying triacylglycerol (TAG) biosynthesis in woody oilseed plants due to the high amount of seed oil, which is important for food and industrial uses. TAG is the major form of stored lipids in seeds and diacylglycerol acyltransferase (DGAT; EC 2. 3. 1. 20) catalyzes the final and critical step of TAG synthesis. Here, two novel DGAT genes, designated XsDGAT1 and XsDGAT2, were cloned from developing X. sorbifolia embryos. Sequence analysis showed that XsDGAT1 had little sequence homology to XsDGAT2. Heterologous expression of XsDGAT1 and XsDGAT2 in TAG-deficient yeast mutants restored TAG synthesis, confirming their biological activity. Expression of the two genes in wild-type Arabidopsis led to TAG synthesis and an increase in total seed oil in transgenic plants, with XsDGAT1 appearing to contribute to TAG synthesis at a greater level. Comparison of the expression patterns revealed that both XsDGAT1 and XsDGAT2 were expressed in the examined tissues and had similar spatiotemporal expression patterns with higher expression in embryos than in leaves and petals. The expression patterns of both XsDGAT1 and XsDGAT2 correlated with oil accumulation in developing X. sorbifolia embryos. These data suggest that XsDGAT1 and XsDGAT2 are both responsible for TAG synthesis in X. sorbifolia seeds.
authors.affiliation: College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China. guohh@bjfu.edu.cn
authors.forename: Hui-Hong
authors.initials: HH
authors.lastname: Guo
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Wang
authors.forename: Qiu-Qi
authors.initials: QQ
authors.lastname: Li
authors.forename: Na
authors.initials: N
authors.lastname: Zhao
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Di
authors.initials: D
authors.lastname: Liu
authors.forename: Qing
authors.initials: Q
authors.lastname: Hu
authors.forename: Feng-Lan
authors.initials: FL
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis; D003001:Cloning, Molecular; D017124:Conserved Sequence; D051048:Diacylglycerol O-Acyltransferase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018628:Gene Dosage; D008969:Molecular Sequence Data; D010802:Phylogeny; D010938:Plant Oils / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D029631:Sapindaceae / Q000201:enzymology* / Q000235:genetics; D012639:Seeds / Q000201:enzymology* / Q000235:genetics; D017422:Sequence Analysis, DNA; D014280:Triglycerides / Q000096:biosynthesis
chemical_list: D010938:Plant Oils; D010940:Plant Proteins; D014280:Triglycerides; D051048:Diacylglycerol O-Acyltransferase
keywords: DGAT; DIG; Diacylglycerol acyltransferase; ER; Embryo development; FAMEs; FID; GC; Gene expression; ORFs; PCR; RACE; Seed oil; TAG; TLC; Triacylglycerol; UTRs; Xanthoceras sorbifolia; daa; days after anthesis; diacylglycerol acyltransferase; digoxigenin; endoplasmic reticulum; fatty acid methyl esters; flame ionisation detection; gas chromatography; open reading frames; polymerase chain reaction; rapid amplification of cDNA ends; thin-layer chromatography; triacylglycerol; untranslated regions