Characterization and Functional Analysis of a Type 2 Diacylglycerol Acyltransferase () Gene from Oil Palm ( Jacq.) Mesocarp in and Transgenic .

Oil palm ( Jacq.) is the highest oil-yielding plant in the world, storing 90 and 60% (dry weight) oil in its mesocarp and kernel, respectively. To gain insights into the oil accumulation mechanism, one of the key enzymes involved in triacylglycerol (TAG) biosynthesis, a Type 2 diacylglycerol acyltransferase (DGAT2) from oil palm, was characterized for its activity. is highly expressed in mesocarp during the last two developmental stages while large amounts of oil are accumulated at the highest rate during ripening. Heterologous expression of in mutant yeast H1246 restored TAG biosynthesis with substrate preference toward unsaturated fatty acids (FAs) (16:1 and 18:1). Furthermore, seed-specific overexpression of in enhanced the content of polyunsaturated FAs 18:2 and 18:3 (each by 6 mol%) in seed TAGs, when compared to that from wild-type Arabidopsis. In turn, the proportion of 18:0 and 20:0 FAs in seed TAGs from EgDGAT2 transgenic lines decreased accordingly. These results provide new insights into understanding the activity of EgDGAT2 from oil palm mesocarp, which will be of importance for metabolic enhancement of unsaturated FAs production.