ANALYSIS OF THE 3 ESSENTIAL CONSTITUENTS OF OIL BODIES IN DEVELOPING SESAME SEEDS

Oil bodies of plant seeds contain a matrix of triacylglycerols surroun ded by a monolayer of phospholipids embedded with alkaline proteins te rmed oleosins. Triacylglycerols and two oleosin isoforms of 17 and 15 kDa were exclusively accumulated in oil bodies of developing sesame se eds, During seed development, 17 kDa oleosin emerged later than 15 kDa oleosin, but it was subsequently found to be the most abundant protei n in mature oil bodies. Phosphotidylcholine, the major phospholipid in oil bodies, was amassed in microsomes during the formation of oil bod ies, Prior to the formation of these oil bodies, a few oil droplets of smaller size were observed both in vivo and in vitro. These oil dropl ets were unstable, presumably due to the lack of steric hindrance shie lded by the oleosins. The temporary maintenance of these droplets as s mall entities seemed to be achieved by phospholipids, presumably wrapp ed in ER, Oil bodies assembled in late developing stages possessed a h igher ratio of oleosin 17 kDa over oleosin 15 kDa and were utilized ea rlier during germination. It seems that the proportion of oleosin 17 k Da on the surface of oil bodies is related to the priority of their ut ilization.