本项目针对甲藻赤潮频发且危害日益严重的现实问题，瞄准“菌藻关系”和“细胞死亡调控机制”研究的科学前沿，以引发我国东海赤潮的第一优势藻种且进化地位特殊的间核生物东海原甲藻为目标藻株，以本课题组新获得的能引起该藻发生类似自噬性死亡的副球菌株Y42为材料，开展该菌株促使赤潮甲藻死亡的系列研究。首先探究菌株Y42促使东海原甲藻类自噬死亡的分子特征和致死机理；其次比较间核生物甲藻的这种新奇死亡方式和原核细胞与真核细胞死亡方式的异同；最后探究这种死亡方式在赤潮消亡过程中的作用。本申请项目将首次从细胞水平、生理生化水平和分子水平对东海原甲藻的死亡方式及其分子特征和调控机制开展研究，这不仅有利于揭示赤潮消亡的分子机理，还能为阐释生命由原核生物→间核生物→真核生物的进化过程提供重要证据。深度探究菌株Y42对东海原甲藻的抑杀过程和作用机理，能为东海原甲藻赤潮的微生物防治提供分子理论基础、菌质资源与技术支撑。

Large-scale blooms caused by a dinoflagellate Prorocentrum donghaiense frequently occurs in the East China Sea in recent years. These blooms are massive, sometimes extending over thousands of square kilometers, and can persist for nearly one month. Although an abundance of the published literature has explained the initiation and decline of all phytonplankton blooms, the degenerative process and molecular mechanism in algal bloom is still not thoroughly understood.We aimed at the practical problem that harmful algal blooms (HABs) caused by P. donghaiense are more and more frequent and serious, focused on frontiers of science research on the the relationship between bacteria and algae and the regulation mechanism of cell death in bloom decline to explore a new way for controlling P. donghaiense blooms..In previous research, we isolated a bacteria Y42 from the HABs forming dinoflagellate P. donghaiense, which showed high algacidal activity against P. donghaiense. The culture of strain Y42 could trigger autophagy-like cell death and leaded P. donghaiense to die out in a short time. This novel autophagy-like cell death was never report in algal cells. To understand the algacidal effects and mechanisms of strain Y42 against P. donghaiense and evaluate the potential for human intervention to harmful algal blooms with microbial control, this project chose P. donghaiense which is the dominant species in spring algal blooms in the East China Sea as objectiv algae and the bacteria Y42 which cuased P. donghaiens autophagy-like cell death as research materials to carry out a series of studies on the algacidal activity of strain Y42 against P. donghaiense. First of all, we explored the molecular characteristics and regulation mechanism of the novel autophagy-like cell death in P. donghaiense caused by strain Y42, and then compared mesokaryote dinoflagellate with prokaryote and eukaryote on cell death mode, process and regulation mechanism. Finally, we studies the role of autophagy-like cell death at the decline stage of P. donghaiense bloom. The project will study on molecular characteristics and regulation mechanism of cell death in P. donghaiens for the first time from cellualr level, biochemical level and molecular level. The study would not only enhance researcher’s understanding of the mechanisms of microbial control to harmful algal blooms, but also provide insights into the trend and mechanism in the evolution of cell death among prokaryotes, mesokaryotes and eukaryotes because of the remarkable evolutionary status of mesokaryotes dinoflagellate. Otherwise, the project would provide scientific basis, bacteria resources, bilological control technology for the effective control of P. donghaiens blooms.