Ontogeny of oil bodies Monitored with the accumulation of their three essential constituents in developing Sesame Seeds

• Main Authors: Peng, chi-chung, 彭及忠
• Other Authors: Jason T.C.Tzen
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/19565447190997884907

碩士 === 國立中興大學 === 農業生物科技學研究所 === 85 === ABSTRACTPlant seeds store triacylglycerols in discrete organelles called oil bodies. An oil body is surrounded by a half-unit membrane of phospholipids and alkaline proteins termed oleosins. Triacylglycerols and two oleosin isoforms of 17 and 15 kDa were exclusively accumulated in oil bodies of developing sesame seeds. During seed development, oleosin 17 kDa emerged later than oleosin 15 kDa, yet developed subsequently into the most abundant protein in mature oil bodies. Phosphotidylcholine, the major phospholipid in oil bodies, was amassed in ER during the formation of oil bodies. The results support that oil bodies originate from ER with actively synthesized triacylglycerols and phosphotidylcholine whereas oleosins target onto budding oil bodies directly without packaging in ER. Prior to the formation of oil bodies, few oil droplets of smaller size were observed in vivo and in vitro. These oil droplets were unstable presumably due to the lack of steric hindrance shielded by oleosins. The temporary maintenance of these droplets as small entities seemed to be provided by phospholipids wrapped in ER. Oil bodies assembled in late developing stages possessed a higher ratio of oleosin 17 kDa over oleosin 15 kDa and were utilized earlier during germination. It seems that the proportion of oleosin 17 kDa on the surface of oil bodies is related to the priority of their utilization.