1-¹⁴C linoleoyl-COA desaturation into diverse lipid classes of dracocephalum moldavica cotyledons

To elucidate factors that contribute to the high 18:3 content of Dracocephalum moldavica (D. moldavica), a pulse-chase study of radiolabled ¹⁴C linoleoyl-CoA was carried out at an early and late stage of embryo triglyceride (TG) synthesis. In D. moldavica ¹⁴C-18:2 incorporation in PC increased and ¹⁴C-18:3 decreased, meanwhile the opposite was observed in TG (the incorporation of ¹⁴C-18:3 in TG is two-fold that of ¹⁴C-18:2 in PC). This suggests that both ω-3 desaturase is effectively desaturating ¹⁴C -18:2 in PC and acyltransferases are selectively transferring ¹⁴C -18:3 into TG. Also ¹⁴C -18:3 increased in D. moldavica TG indicates that most of the 18:2 was desaturated to 18:3 before transfer to the free fatty acid/acyl-CoA pool in D. moldavica.