拟南芥辐射旁效应信号转导的关键基因研究

The radiation-induced bystander effect in vivo in plants was carried out for the understanding of the low-energy-ion mutagenesis. The distant signal transduction was reported to be implicated in the low-energy-ion mutagenesis in plants, whereas the underlying molecular mechanism is so far clear. At present, it is necessary to isolate and characterize some genes involved in the generation of bystander signal(s) and the bystander responses...In this proposal, a T-DNA insert mutant library is first established, with the Arabidopsis 15-6# line transgenic for AtRAD54 promoter::GUS as the genetic background, which was widely used in the analysis of bystander effects in vivo in plants. Due to the brief experimental process of the 15-6# line, the function-loss mutants in bystander effect can be screened rapidly from the T-DNA insertion library. After isolating some of the related mutants, their wildtype genes will be then determined to take part in the gneration of signal(s) in irradiated tissues or distant induction of effect in bystander tissues, or both, using the Arabidopsis root micro-grafting. Finally, a primary outline regarding the signaling pathways of bystander effect in plants will be drawn based on the biological function of the isolated genes and their roles in signal transduction. The work will be significant for investigating further the underlying molecular mechanism of low-energy-ion mutagenisis.

为解释低能离子植物诱变机制而开展的植物辐射旁效应研究，目前已经取得了一定的进展，证明辐射诱导的远程信号转导可能是低能离子诱导植物遗传变异的重要基础之一，但是目前植物辐射远程诱导的分子机制还远未清晰，参与辐射损伤信号产生、远程诱导的关键基因和信号途径还亟待阐明。本项目主要是利用拟南芥15-6#辐射旁效应实验体系简单快捷，便于批量操作的特点，和拟南芥成熟的T-DNA插入突变技术有机结合，构建辐射旁效应相关基因的快速筛选体系。拟通过大量的筛选和后续的遗传分析，定位、克隆部分参与植物辐射旁效应的相关基因。在此基础上使用拟南芥根局部辐射微嫁接技术确定目的基因参与植物辐射旁效应的过程。最后借助拟南芥遗传信息资源库和生物途径数据库，关联目的基因的生物学功能及其所属的信号通路，构建一个植物辐射旁效应信号转导通路的初步框架，为更深入的研究低能离子诱变的内在分子机理奠定基础。

本项目以模式拟南芥作为研究对象，通过T-DNA插入突变筛选和DNA表达谱芯片分析，发现植物激素和表观遗传相关基因能很好地响应局部电离辐射。进一步的实验表明：茉莉酸、水杨酸信号通路在植物个体内、个体间辐射旁效应诱导中有着关键的角色，也同时发现DNA甲基化和基因转录沉默表观机制参与了植物辐射旁效应的诱导。微重力信号通路和植物辐射旁效应之间耦合关联性也被验证，植物生长素介导了它们之间的耦合。本项目所取得的结果为我们从非靶效应的角度解释低能离子的诱变机制、精确评估空间辐射的健康风险、增进防护策略提供了很好的理论依据。