Comparative Proteomic Analysis Of Space Radiation And Simulated Heavy Ion Radiation Of Rice

In order to explore the biological effects and the molecular mechanisms of space radiation on plants,this paper carried out experiments on rice irradiated by "Shijian-10"space flight and ground simulated carbon ion radiation.The biological effects were studied in multidimensional ways from the phenotype,photosynthetic efficiency,antioxidant level and functional protein expression profiles.The similarities and differences between space and simulated heavy ion radiations were analyzed and some radiation sensitive protein markers were futher investigated.The results showed that the effects of " Shijian-10 " space flight and ground heavy ion(Linear energy transfer,LET-30KeV/?m)radiation on rice were different.Space flight could promote rice growth and the photosynthetic efficiency,while 0.2Gy and 2Gy doses of simulated radiation produced inhibitory effects.Space flight and high dose simulated radiation of 2Gy could induce oxidative damage by reactive oxygen species(ROS)in rice cells.The activity of ROS scavenging system and the expression level of related proteins were significantly enhanced.However,the low dose of 0.2Gy simulated radiation did not cause significant oxidative damage.Cytochrome b6f protein complex and photosystem ? center proteins which are involved in the process of photosynthetic electron transport in rice,were sensitive to both of the space flight and heavy ion radiations.The results further showed that space flight caused a wide range of functional protein responses,space flight broke down the homeostasis of rice cells,reduced the synthesis of protein and stored energy metabolism of starch for adapting to oxidative stress induced by chronic ROS.And microgravity was also involved in the regulation of the cell wall process,which indicated spaceflight was a synergetic effect.High and low doses of simulated radiation did not cause a wide range of functional protein responses except for photosynthetic process.Only high dose of simulated radiation could lead to similar oxidative stress responses and protein metabolism changes as space radiation.