INFORM October 2025

inform October 2025, Vol. 36 (9) • 19

In typical oilseeds, the final acylation step of TAG is cata lyzed by diacylglycerol acyltransferase (DGAT1), which incor porates a long-chain fatty acid onto the sn -3 position of diacylglycerol (DAG). Acetyl-TAGs use a different enzyme; dia cylglycerol acetyltransferase (DAcT) transfers an acetyl group from acetyl-CoA to the same DAG substrate. Our first focus was to identify and isolate DAcT enzymes from Euonymus species. We conducted a comparative transcriptomic analysis on the developing endosperm and aril tissues of the Euonymus alatus fruit using pyrosequencing technology. Commonly known as the Burning Bush, Euonymus alatus is a popular ornamental plant used in landscaping due to its bright red leaves in the fall. The transcriptomic analysis revealed an uncharacterized acyltransferase that was abundant in Euonymus alatus endo sperm but absent from the aril, matching the accumulation pattern of acetyl-TAG in these tissues. The acyltransferase was isolated—now called EaDAcT ( Euonymus alatus diacylglycerol acetyltransferase)—to test its function. When expressed in yeast, EaDAcT produced acetyl-TAGs but lacked regular TAGs production, confirming its substrate specificity. This marked the first isolation of a gene specifically responsible for ace tyl-TAG biosynthesis.

To express EaDAcT in plants, we designed a construct with a seed-specific promoter and DsRed fluorescent marker to visually select the transgenic seeds. We introduced this con struct into camelina using Agrobacterium -mediated floral dip transformation with vacuum infiltration. In our best-perform ing lines, acetyl-TAGs reached 65 mol percent, a significant metabolic shift in camelina oil composition, though still below native levels found in Euonymus . This first step validated our ability to redirect lipid metabolism toward acetyl-TAGs in engi neered oilseeds and set the stage for further optimization. SELECTING A BETTER ENZYME Following the discovery of EaDAcT, our lab screened several EaDAcT homologs isolated from other Euonymus or Celastrus species. Similar to EaDAcT, these all lacked long-chain acyl transferase activity and instead catalyzed the production of acetyl-TAGs using DAG and acetyl-CoA as substrates. However, their acetyltransferase activity varied considerably. EfDAcT, from Euonymus fortunei , showed the highest activity in vitro, and yeast cultures expressing EfDAcT produced more ace tyl-TAG than those expressing EaDAcT. We next tested whether EfDAcT could outperform EaDAcT in plants. We introduced EfDAcT into camelina. On aver age, EfDAcT expression in camelina led to a 20 mol percent

We’re excited to introduce two new series to the Laboratory Proficiency Program— Lecithin and Avocado Oil . LABORATORY PROFICIENCY PROGRAM. DISCOVER WHAT’S NEW FROM THE

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