分子设计ROS清除系统增强油菜菌核病抗性

活性氧（ROS）是一种重要的信号分子，参与植物多种生物学过程。核盘菌侵染寄主诱导ROS的积累。过量ROS对寄主和核盘菌细胞均具有毒害作用。我们前期发现核盘菌从寄主中掠夺铜离子激活Cu/Zn SOD等抗氧化酶，清除体内的ROS，减少ROS对自身细胞的毒害，而感病寄主细胞的“铜离子动态平衡”代谢的基因下调表达，ROS清除系统被破坏，积累过量的ROS诱导寄主细胞程序式死亡。本项目拟构建核盘菌侵染诱导型启动子，增强油菜Cu/Zn SOD合成基因BnCSD和其铜离子分子伴侣基因BnCCS的表达，提高油菜细胞ROS清除系统的活性，降低油菜细胞内的ROS水平；并利用寄主诱导基因沉默（HIGS）技术干扰核盘菌相应基因的表达，抑制核盘菌细胞ROS清除系统活性，达到抑菌抗菌增强油菜菌核病抗性的目的。本研究的开展将有助于增加了解寄主与核盘菌的互作，挖掘基因资源开展油菜抗病的分子设计育种具有重要的理论和实践意义。

Reactive oxygen species (ROS) are important signaling molecules in variant biological processes in plant. The infection of Sclerotinia promotes host to produce excess ROS, which are toxic to cells in both host and Sclerotinia. In the previous study, we found that host copper ion was hijacked to active Cu/Zn SOD by sclerotinia for scavenging ROS in Sclerotinia cells, and that the genes expression of ‘cooper ion homeostasis’ were depressed and the power to scavenge ROS was decreased in susceptible host, resulting in excess ROS which induce host programmed cell death processes. In this proposal, the ROS scavenging system of rapeseed will be designed 1) to enhance the power to detoxify ROS by over-expressing BnCSD (encoding Cu/Zn SOD) and BnCCS (encoding copper chaperone which delivers Cu into Cu/Zn SOD), and 2) to specifically interrupt the expression of SsSOD and SsCCS in sclerotinia with the technology of host-induced gene silencing (HIGS). This study will be helpful for understanding the interaction between host and Sclerotinia, and widening the range of screening gene sources for rapeseed resistance breeding.