叶绿体蛋白PsbO在马铃薯X病毒侵染过程中的作用研究

Increasing number of interactions between chloroplast proteins and viral proteins have been identified to date. Chloroplast protein PsbO(33kDa) is a key component of the oxygen-evolving complex (OEC) in photosynthetic system II, which also has an important role in stabilizing the entire complex. PsbO interacts with PVX p25 in previous work. The ability of systemic infection was dramatically enhanced when PVX was inoculated on TRV based PsbO VIGS plants. This study aims to reveal the role of PsbO played in PVX infection and host plant resistance and figure out the detailed information about PsbO in plant RNA silencing system. Microarray data sourced from TRV based PsbO VIGS plant and PsbO over expressed transgenic plant will be utilized to explore plant resistance gene associated with PsbO. All these studies will let us know better about relationship between PsbO and plant resistant genes including specific function of p25.

叶绿体蛋白与植物病毒蛋白之间的相互作用日趋受到人们的重视。放氧复合体亚基蛋白PsbO(33kDa)是叶绿体光合系统II中放氧复合体的关键组成成份之一，它对整个复合体的稳定具有重要的作用。前期研究发现PsbO蛋白与马铃薯X病毒(potato virus x,PVX)p25蛋白能发生相互作用，利用烟草脆裂病毒(TRV)进行病毒诱导基因沉默(VIGS)沉默PsbO后，病毒在沉默植株的系统扩散能力明显加强。本研究旨在揭示PsbO蛋白在PVX侵染和寄主植物抗性中发挥作用的同时以该蛋白与植物RNA沉默系统的联系为切入点，明确该蛋白在RNA沉默系统中发挥的功能及环节，结合VIGS下调该基因植株和转基因过量植株表达谱芯片等数据，归纳分析与PsbO蛋白有相互关联的植物抗性基因。本研究对了解PsbO与植物寄主抗性之间的关系及PVX p25功能的细节有重要理论价值。

马铃薯X病毒属病毒在世界范围内普遍发生，对经济作物造成严重损失。马铃薯X病毒（potato virus x, PVX）是该属的代表种。在研究PVX侵染本氏烟的过程中，我们筛选到两个与之相关的寄主蛋白PsbO和H2B。PsbO蛋白与能与PVX p25蛋白能发生相互作用，利用烟草脆裂病毒（tobacco rattle virus, TRV）介导病毒诱导基因沉默（virus induced gene silenced, VIGS）下调表达PsbO后，PVX在沉默植株的侵染能力明显加强，究其机制是沉默PsbO后，提高了PVX的复制和细胞间运动能力，同时寄主植物自身用于抵抗病毒的RNA silencing 能力也相应减弱。相反，利用TRV介导沉默H2B后，沉默植株对PVX侵染具有一定的抗性，且研究发现H2B沉默的本氏烟中对PVX的抗性与其内源SA的积累有关，内源SA的积累能够激活植物的RNA silencing系统，使之用于抵抗PVX的侵染。本项目的研究结果将为明确PVX的致病过程和挖掘植物抵抗PVX侵染途径提供实验基础。