侧生分生组织是植物能够形成分枝的基础。侧生分生组织的形成标志着新的分生组织中心建立，使植物具有产生叶片、花的新生长点。然而关于侧生分生组织形成的研究开展不多，相关知识匮乏。为解析调控侧生分生组织发生的调控网络，本研究拟结合细胞特异转录组分析、全基因组酵母单杂交筛选、化学诱导激活等多种基因组水平研究技术系统研究这个重要的发育过程，找到一批新的调控因子，以揭示调控此干细胞组织中心建成的机制。我们的前期研究已经建立了必要的基因组水平研究方法和活体成像等技术体系，发现了激素对侧生分生组织发生的重要作用，并初步获得了一些新的侧生分生组织发生调控因子。本研究将利用这些技术手段在全基因组水平解析转录调控网络，根据前期研究得到的线索并利用已获得材料深化认识侧生分生组织发生的机理。侧生分生组织在营养生长期和生殖生长期的活性分别决定着作物的穗数和穗粒数，因此对侧生分生组织的研究将为分子育种提供理论支撑。

Shoot branching in higher plants depends on the activity of axillary meristem. The initiation of axillary meristem establishes new growth axis, from which organs, such as leaf, may initiate. Despite of its significance to plant development, research on axillary meristem initiation remains rudimentary. To systematic dissect the regulatory network underlying axillary meristem initiation, we combine several genome-scale technologies, including cell type-specific genome expression analysis, genome-wide yeast-one-hybrid screen, and chemical inducible gene activation, to study axillary meristem initiation. We recent findings and preliminary work has established these genome-scale technologies, as well as a live imaging system, and identified two phytohormones as key regulators of axillary meristem, in addition to identifying a number of genes affecting axillary meristem initiation. In this proposed work, we will expand these technologies to the genome scale to decipher the regulatory network controlling axillary meristem initiation, and to identify mechanisms controlling axillary meristem initiation by extending our recent finding of phytohormonal regulation and by utilizing our newly identified key genes. Because the activities of axillary meristem in the vegetative stage and the reproductive stage of plant development decide tiller number per plant and seeds number per tiller in crops, understanding of the axillary meristem initiation process will greatly support molecular breeding practice.