‘Diacylglycerol acyltransferase (DGAT)’ acts as a key rate-limiting enzyme that catalyzes the final step of the
de novo biosynthesis of triacylglycerol (TAG). The study was to characterize the function of the
DGAT3 gene in
Paeonia rockii, which is known for its accumulation
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‘Diacylglycerol acyltransferase (DGAT)’ acts as a key rate-limiting enzyme that catalyzes the final step of the
de novo biosynthesis of triacylglycerol (TAG). The study was to characterize the function of the
DGAT3 gene in
Paeonia rockii, which is known for its accumulation of high levels of unsaturated fatty acids (UFAs). We identified a
DGAT3 gene which encodes a soluble protein that is located within the chloroplasts of
P. rockii. Functional complementarity experiments in yeast demonstrated that
PrDGAT3 restored TAG synthesis. Linoleic acid (LA, C18:2) and α-linolenic acid (ALA, C18:3) are essential unsaturated fatty acids that cannot be synthesized by the human body. Through the yeast lipotoxicity test, we found that the yeast cell density was largely increased by adding exogenous LA and, especially, ALA to the yeast medium. Further ectopic transient overexpression in
Nicotiana benthamiana leaf tissue and stable overexpression in
Arabidopsis thaliana indicated that
PrDGAT3 significantly enhanced the accumulation of the TAG and UFAs. In contrast, we observed a significant decrease in the total fatty acid content and in several major fatty acids in
PrDGAT3-silenced tree peony leaves. Overall,
PrDGAT3 is important in catalyzing TAG synthesis, with a substrate preference for UFAs, especially LA and ALA. These results suggest that
PrDGAT3 may have practical applications in improving plant lipid nutrition and increasing oil production in plants.
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