活性氧调控花药绒毡层细胞程序性死亡的分子机理研究

项目名称： 活性氧调控花药绒毡层细胞程序性死亡的分子机理研究

项目编号： No.31471304

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 生物科学

项目作者： 张彦

作者单位： 山东农业大学

项目金额： 80万元

中文摘要： 植物雄性不育广泛应用于杂交制种、杂种优势利用、增加遗传多样性等方面。花药绒毡层细胞程序性死亡（PCD）异常是雄性不育的一个主要成因。近年来的研究揭示了调控花药绒毡层PCD的关键转录因子以及转录调控网络。然而，对于这些转录因子调控的下游信号途径并不清楚。此外，最新的研究表明活性氧（ROS）参与水稻花药绒毡层PCD，但并不清楚花药绒毡层ROS的来源、ROS与绒毡层转录调控网络间的关系、以及绒毡层ROS的下游信号途径。申请人发现拟南芥编码NADPH氧化酶的RBOH基因在花药绒毡层细胞中表达。其功能缺失造成绒毡层PCD延迟、花粉败育，而过量表达RBOH基因导致绒毡层PCD提前，同样造成花粉败育。本课题拟通过综合使用分子生物学、遗传学和细胞学等手段对其表达及活性的调控机制以及ROS的下游信号途径进行深入解析，以期探究上述的几个关键科学问题，并且有助于利用遗传工程创制雄性不育系。

中文关键词： 雄性不育；活性氧；花粉发育；程序性细胞死亡；NADPH氧化酶

英文摘要： Male sterility in angiosperms has been extensively studied due to its wide applications in the agricultural industry. Tapetum is a layer of cells adjacent and of vital importance to developing microspores by providing constructing materials through a programmed cell death (PCD) process, in which transcriptional cascades and proteolytic activities play key roles. As universal signals for developmental PCD, reactive oxygen species (ROS) were involved in this process since failures in ROS scavenging led to male sterility. However, it is unclear from what sources ROS are generated, whether there is temporal ROS amplitude, how the ROS-producing system interacts with the tapetal transcriptional network, and its downstream signaling pathway contributing to tapetal PCD. Preliminary studies in our laboratory showed that two Arabidopsis RESPIRATORY-BURST OXIDASE HOMOLOG (RBOH) genes are spatiotemporally expressed in tapetum during anther development stage 6-10. Functional loss of these RBOH genes resulted in pollen abortion due to delayed tapetal degeneration. By contrast, overexpression of RBOH under a tapetum-specific promoter led to pollen abortion due to precocious tapetal PCD. These results indicated that spatiotemporal ROS in tapetum was mainly controlled by NADPH oxidases. We propose to fine dissect the molecular and cellular mechanisms underlying ROS-mediated PCD. Results obtained from this study not only provide answers to pressing questions as mentioned above, but also contribute to the generation of new germplasms useful for hybrid production.

英文关键词： male sterility;reactive oxygen species;pollen development;programmed cell death;NADPH oxidase