水稻株型是决定其产量的核心因素之一，而叶倾角是水稻株型的重要组成部分。前期研究表明过表达水稻DREB类转录因子基因OsDREBA5-1导致植株叶倾角增大，而抑制其表达则使植株叶倾角变小。通过形态解剖、生理生化和相关基因表达分析，推测OsDREBA5-1可能通过参与BR信号转导调控叶角的形态建成，但调控机制还不清楚。本项目拟在前期工作的基础上，进一步分析OsDREBA5-1组织表达特征、受激素诱导表达及下游调控基因的表达情况；进行ChIP-seq分析，确定直接调控的下游关键基因；通过酵母双杂交技术筛选OsDREBA5-1的互作蛋白，并通过GST Pull-Down、BiFC技术进行体外、体内验证；创建OsDREBA5-1互作蛋白基因、下游调控基因的过表达、RNAi突变株，并进行初步功能鉴定。研究结果将进一步揭示OsDREBA5-1调控水稻叶倾角的分子机理，为水稻株型改良提供理论依据。

Leaf angle is an important component of rice (Oryza sativa) plant architecture that plays a crucial role in determining grain yield. We previously have found that overexpression of OsDREBA5-1, a DREB family transcription factor gene, leaded to increased leaf angle, while decreased its expression by RNAi resulting in an opposite phenotype. Based on the results of morphological anatomy assay, physiology and biochemistry assay and related gene expression analysis, we suggested that OsDREBA5-1 affected leaf angle through a BR-dependent signaling pathway. However, the molecular mechanism of OsDREBA5-1 in rice leaf angle control is still unknown. Based on our previous research, we propose the following project to clarify the molecular mechanism of OsDREBA5-1 in rice leaf angle control: examine the expression profiles of OsDREBA5-1 indifferent tissues and under different phytohormone treatments with different concentrations; analyze the expressions of the downstream genes of OsDREBA5-1 in WT and OE, RI transgenic rice plant; identify the downstream target genes of OsDREBA5-1 protein by ChIP-seq; identify the possible interacting proteins of OsDREBA5-1 by yeast two hybrid assay, followed by GST Pull-Down and BiFC confirmation in vitro and in vivo, respectively; perform preliminary functional characterization of the interacting protein genes and downstream genes of OsDREBA5-1. This work will contribute to understanding of the molecular mechanism of OsDREBA5-1 in leaf angle control. The results will also provide theoretical foundation for rice plant architecture improving.