COEXISTENCE OF BOTH OLEOSIN ISOFORMS ON THE SURFACE OF SEED OIL BODIES AND THEIR INDIVIDUAL STABILIZATION TO THE ORGANELLES

The oil bodies of plant seeds contain a triacylglycerol matrix surroun ded by a monolayer of phospholipids embedded with alkaline proteins te rmed oleosins, Two distinct oleosin isoforms with molecular masses of 18 and 16 kDa are present in rice oil bodies, Chicken antibodies raise d against oleosin 18 kDa and rabbit antibodies raised against oleosin 16 kDa did not cross-recognize these two homologous isoforms, This pec uliar non-cross recognition was used to locate the two oleosin isoform s on the surface of oil bodies via immuno fluorescence detection using anti-chicken IgG conjugated with FITC (fluorescein isothiocyanate) an d anti-rabbit IgG conjugated with Texas-Red, The results revealed that both oleosin isoforms resided on each oil body in vivo and in vitro. Artificial oil bodies were reconstituted via sonication using triacylg lycerol, phospholipid, and oleosins, The results indicated that the tw o rice oleosin isoforms could stabilize artificial oil bodies individu ally whereas oleosin 16kDa provided better stability to the organelles than oleosin 18 kDa.