水稻抽穗期微效QTL-DTH3b的功能研究

抽穗期是水稻适应不同栽培区域和种植季节的一个重要农艺性状。我们构建并筛选到一个以Aso为背景近等基因系NIL(DTH3b)。与Aso相比，NIL(DTH3b)在长日照条件下抽穗延迟约一周。通过定位及遗传互补实验，确定了控制该性状的基因为ORF4/DTH3b。DTH3b为一个未知功能新基因。DTH3b为一个核蛋白。通过酵母双杂交筛选，我们确认了一个与DTH3b互作的蛋白，命名为DTH3b-Interacting Protein 1 (DIP1)。本项目拟在前期工作基础上，对DTH3b以及DIP1的基本性质进行研究；同时确认DTH3b和DIP1在抽穗期调控网络中的位置；利用CRISPR技术构建DTH3b与DIP1的单、双突变体，在表型分析的基础上，解析互作的生物学意义；同时对DIP1直接结合的靶基因进行探索研究；以期揭示DTH3b控制水稻抽穗期的分子机制，同时为抽穗期性状分子设计育种提供支持。

Heading date in rice is an important agronomic trait that determines the cropping regional and seasonal adaptability. We selected a homologous NIL (viz. NIL(DTH3b)) that only carrying a 12 cM homozygous IR24 chromosome segment with DTH3b in Aso background. Compared with Aso, NIL(DTH3b) showed 7-days delayed flowering in Beijing NLDs, while no differences in Hainan NSDs. We confirmed ORF4/DTH3b was responsible for the delay heading phenotype by fine mapping and genetic complementary assay. DTH3b is an unknown function protein. DTH3b is a nuclear-localization protein. We got DTH3b-Interacting Protein 1(DIP1) which interacts with DTH3b. Based on these data, we further study the tissue-expression pattern and rhythm-expression pattern of DTH3b and DIP1, and study the upstream and downstream genes regulated by DTH3b and DIP1 in genetic net of heading date; we also construct dth3b, dip1, and dth3bdip1mutants using CRISPR/Cas9 methods, and analyze the phenotype of these mutants, to investigate the biological means of DTH3b-DIP1 interaction; at the same time, we investigate the target genes regulated directly by transcription factor DIP1. The aim of this study is the explanation of molecular mechanism of DTH3b controlling heading date and providing theoretical foundation for molecular design breeding.