Accumulation of C20 and C22 unsaturated fatty acids in triacylglycerols from developing seeds of Limnanthes alba

In Limnanthes alba seeds, an accumulation of phosphatidic acid (PA) occurred during seed development until the day 15 after pollination (DAP). Between the 15 and the 20 DAP, a rapid synthesis of triacylglycerols (TG) took place with a simultaneous decrease of PA. During the same period, very long-chain fatty acids (VLCFA), viz. 20: 1 Δ⁵, 22:1 Δ¹³ and 22:2Δ^5,13 were synthesized and rapidly channelled into TG. These results suggest the involvement of glycerol-3-phosphate in TG biosynthesis. Moreover, TG synthesis appears to be a time-compartmentalized event; the first accumulation of PA having short-chain acyl moieties then, from the 15 DAP, synthesis of VLCFA which are esterified in TG originating from the PA accumulated during the first period.