NAC家族成员参与调控木质部发育，并且可能在生长素的调控下参与林木晚材的形成，然而相关的研究尚未见报道。本研究拟从楸树基因组中克隆出在晚材形成时期显著上调表达的CbuNAC1，利用原位杂交和遗传转化启动子的方法精确检测外施IAA或NPA对楸树新生木质部中CbuNAC1表达的影响，明确IAA对CbuNAC1的调控作用；通过观察CbuNAC1过量或抑制表达后的楸树转基因植株木质部解剖结构的变化，揭示CbuNAC1在晚材形成过程中的功能，并结合CbuNAC1的表达模式分析明确IAA—CbuNAC1通路在晚材形成过程中作用；利用cDNA文库筛选、凝胶阻滞试验，筛选并验证调控CbuNAC1在晚材形成时期上调表达的上游调控因子，深入构建相关调控网络。本研究有望阐明IAA—CbuNAC1介导的晚材形成的相关调控机制，为人工调控楸树的晚材率奠定理论基础，并且为楸树材性遗传改良育种策略的制定提供了新的思路。

NAC Transcription factor family members participate in xylem development and may also be involved in latewood formation under the regulation of auxin, however, further investigations have not been reported yet. Here, we plan to clone the CbuNAC1 that specific up-regulated in the latewood period of Catalpa bungei; To precisely reveal the function of auxin on regulating CbuNAC1 expression, we will also study the CbuNAC1 expression changes in xylem of IAA and NPA using in-situ hybridization and genetic transformation of CbuNAC1 promotor; Moreover, we are going to observe the xylem anatomy changes, when the expression of CbuNAC1 were overexpressed and repressed in Catalpa bungei, try to verify the IAA—CbuNAC1 pathway that participate in the latewood formation, combine with the expressional pattern of CbuNAC1. Furthermore, cDNA library screening and electrophoretic mobility shift assay (EMSA) will be conducted to select and verify upstream transcription factor of CbuNAC1 during the latewood formation. Taken together, our project would preliminarily construct the regulatory net of latewood formation that mediated by IAA—CbuNAC1 pathway. This study would make a foundation for the artificial regulation of Catalpa bungei latewood rate and provide a new idea for wood property improvement in Catalpa bungei genetic breeding.