Cloning and functional analysis of two type 1 diacylglycerol acyltransferases from Vernonia galamensis

Keshun Yu, Runzhi Li, Tomoko Hatanaka, David Hildebrand

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Vernonia galamensis accumulates vernolic acid (cis-12-epoxyoctadeca-cis-9-enoic acid) as the major fatty acid in its seed oil. Such epoxy fatty acids are useful in a number of industrial applications. Successful genetic engineering of commercial oilseed crops to produce high levels of vernolic acid depends on a better understanding of the source plant enzymes for vernolic acid accumulation. Developing V. galamensis seed microsome assays demonstrate that diacylglycerol acyltransferase (DGAT), an enzyme for the final step of triacylglycerol synthesis, has a strong substrate preference for vernolic acid bearing substrates including acyl-CoA and diacylglycerol. There are two classes of DGATs known as DGAT1 and DGAT2. Here we report on the isolation, characterization, and functional analysis of two DGAT1 cDNAs from V. galamensis (VgDGAT1a and VgDGAT1b). VgDGAT1a and VgDGAT1b are expressed in all plant tissues examined with highest expression in developing seeds. Enzymatic assays using isolated microsomes from transformed yeast show that VgDGAT1a and VgDGAT1b have the same DGAT activity levels and substrate specificities. Oleoyl-CoA and sn-1,2-dioleoylglycerol are preferred substrates over vernoloyl-CoA and sn-1,2-divernoloylglycerol. This data indicates that the two VgDGAT1s are functional, but not likely to be responsible for the selective accumulation of vernolic acid in V. galamensis seed oil.

Original languageEnglish
Pages (from-to)1119-1127
Number of pages9
Issue number5
StatePublished - Mar 2008

Bibliographical note

Funding Information:
This work was supported by the United Soybean Board, the Kentucky Soybean Promotion Board, the Kentucky Science & Engineering Foundation, Ashland Inc., and the Consortium for Plant Biotechnology Research.


  • Asteraceae
  • Diacylglycerol acyltransferase
  • Enzyme activity
  • Gene expression
  • Substrate specificity
  • Triacylglycerol metabolism
  • Vernolic acid
  • Vernonia galamensis

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Plant Science
  • Horticulture


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