侧枝的发育是决定植株形态的一个重要因子，是用材树种遗传改良的重要性状之一。分离与用材树种侧枝发育相关的重要基因，解析其调控的分子机制，可为用材树种的遗传改良提供重要基因资源和科学依据。在前期研究中，我们发现BlSPL8过表达光皮桦植株表现出侧枝生长受到明显抑制的表型，该基因很可能是调控光皮桦侧枝形成的重要调控基因。本课题拟利用表达模式分析、基因编辑技术等技术，分离鉴定BlSPL8上游的miR156基因，研究miR156/BlSPL8基因调控侧枝发育的功能；通过酵母单杂交和高通量测序技术，分离鉴定miR156/SPL途径下游调控侧枝发育的关键基因，解析该途径的调控机制；通过激素处理探讨GA信号在侧枝发育过程中与miR156/SPL途径的交互关系。期望为揭示林木侧枝发育分子调控机理提供重要信息，为光皮桦等用材树种的遗传改良提供重要基因资源和科学依据。

Shoot branching is not only a crucial development process in determining the plant architecture, but also an important trait for genetic breeding in timber trees. To isolate shoot branching related genes and elucidate the underlying regulation mechanism are necessary for genetic improvement of timber trees. Our previous works indicated that overexpression of BlSPL8 in Betula luminifera led to severe inhibition of the lateral bud outgrowth. It implied that BlSPL8 should be an important regulator for shoot branching in B. luminifera. In this project, through expression analysis and genome editing technology, the upstream miR156 genes will be identified, and the regulation functions of miR156/BlSPL8 will be elucidated. By using Yeast one hybrid and deep sequencing, the key genes downstream the miR156/BlSPL8 pathway will be identified, then the regulation network of this pathway will be outlined. Furthermore, the interaction between GA signaling and miR156/BlSPL8 pathway will also be explored. Hopefully, our project will bring important information to understand shoot branching in timber tree, and provide significant gene resource for genetic improvement of B.luminifera.