KRPa基因调控水稻多胚生殖的机理与应用研究

多胚生殖是具有生物学共性的基础科学问题，也是农作物实现杂种优势固定的重要途径。水稻中多胚生殖的调控基因及调控机理至今未知。我们通过敲除水稻KRPa基因得到了稳定、高效的多胚生殖株系，其中部分多胚苗被鉴定为单倍体，可应用于诱导水稻无融合生殖。遗传互补可将突变体回复到单胚生殖表型。KRPa编码一个在种子中优先表达的细胞周期蛋白依赖性激酶抑制因子。我们推测KRPa可能通过调控配子细胞的分裂状态来决定细胞的分化命运。本研究旨在明确KRPa在水稻胚胎发育中的生物学功能；确认krpa调控多胚生殖的细胞学基础；鉴定KRPa的互作蛋白，阐明KRPa的分子调控机制。同时，我们还将尝试遗传操控KRPa在杂交稻背景中诱导无融合生殖，探索基因在水稻杂种优势固定方面的应用潜力。本研究的实施将丰富我们对多胚生殖的调控机制的了解，并为创制新的水稻无融合生殖材料提供优良的基因资源。

Polyembryony is a fundamental question in reproductive biological research, as well as a key way to fix heterosis in crop production. So far, what genes and how do they regulate polyembryony remain blank in almost all species. By knocking out KRPa gene in Nipponbare background, we obtained rice lines generating stable and high ratio of polyembronic progenies. Some of the polyembronic seedlings have been cytologically identified as haploid, showing great potential in apomixes induction and heterosis fixation. Genetic complementation rescued the mutant to single embryo reproduction as the WT. KRPa encodes a cyclin-dependent kinase inhibitor which is predominantly transcribed in developing seeds. We hypothesized that KRPa regulates gametocyte cell cycling to determine the differentiation fate of cells in reproduction. This proposal aims to characterize the biological function of KRPa in rice embyony, investigate the cytological features of krpa in polyembryonic development, and elucidate the molecular mechanism of KRPa-regulated rice embryony by searching proteins interactive with KRPa. Moreover, we will attempt to genetically manipulate KRPa in hybrid rice background to induce apomixes, and explore its potential in crop heterosis fixation. The output of this study will greatly enhance our understanding of polyembryonic development, and provide useful gene resource for rice apomixes indcution.