穗粒数与芒是水稻重要的驯化性状，然而控制这些性状改变的分子机理尚不明确。我们在前期分离了一个调控穗粒数和芒发育的新基因GNA1 (Grain Number and Awn 1，穗粒数和芒1)，该基因编码1个NAC转录因子，从芒原基形成时期起，显著促进芒发育，且对An-1、AWN-2、An-3有加性效应。本项目拟利用互补技术验证候选基因的功能；通过GNA1的基因表达模式分析，功能变异位点研究，亚细胞定位分析，转录激活活性分析，蛋白互作因子的分离，GNA1与An-1、AWN-2、An-3的相互关系分析，GNA1对植物激素的调控作用分析，揭示GNA1的作用机理。研究结果不仅能够阐明GNA1调控水稻穗粒数和芒发育的分子机理，同时也为水稻产量性状的遗传改良奠定基础。

Grain number and awn are key traits associated with the domestication in rice. However, the molecular mechanisms responsible for the transition of these traits still remain unknown so far. In the previous work, GNA1 (Grain Number and Awn 1) regulating grain number and awn development had been isolated. GNA1 encodes a transcription factor protein, it remarkably promotes awn development beginning at the formation of awn primordia stage and shows additive effect on An-1,AWN-2,An-3. In this proposal, we will focus on the following aspects: ①to verify the function of GNA1 by complementation test. ②to reveal the regulation mechanisms of GNA1 by analyzing the expression patterns of GNA1，the functional variation site of GNA1, the subcellular localization and transcription activation activity of GNA1 and gna1, the interaction factor of GNA1 and gna1, the relation between GNA1 and An-1, AWN-2, An-3, the relation between GNA1 and plant hormone, respectively. These results will contribute to not only reveal the function of GNA1 and elucidate the molecular mechanism regulating grain number and awn development, but also provide the theoretical base for genetic improvement of rice yield traits.