周质微管由α-(TUA)和β-(TUB)聚合而成，是植物特有细胞骨架系统，在细胞壁沉积过程中通过指导纤维素合成方向调控细胞壁合成，进而影响木材材性如微纤丝角度。然而，在具有丰富次生细胞壁木本植物中，其具体作用机制仍不清楚。我们前期工作鉴定在杨树中共有8个TUA和21个TUB基因。其中PeTUA1在次生木质部特异表达，并且在具有丰富纤维素的应力木中表达量升高。另外不同翻译后修饰PeTUA1蛋白定位于次生细胞壁加厚不同阶段。在此工作基础上，本项目拟对PeTUA1及翻译后修饰位点突变基因进行过量表达和基因敲除，通过对杨树次生细胞壁和木材材性分析,阐明该基因在木材形成次生细胞壁加厚过程中生物学功能；同时利用应力木诱导体系和激光显微切割技术结合转录组测序手段鉴定PeTUA1基因参与基因调控网络。最终解析杨树微管基因对次生细胞壁合成及木材材性调控机理。此研究结果将为培育优质木材林木品种提供理论依据。

Cortical microtubules comprise of polymers of α- (TUA) and β-tubulin (TUB), which are plant specialized cytoskeletal structures critical for the regulation of cell wall biogenesis, whose function relies on the proposed role of microtubules governing the orientation of cellulose microfibrils during deposition, thus effecting wood properties such as MFA. However, the molecular underpinnings have yet to be explored in woody plants, which have abundance of secondary cell walls. In our previous study, we have identified 8 TUAs and 21 TUBs in Populus genome. Among them, PeTUA1 is highly expressed in secondary xylem (wood) as well as in tension wood (more abundance with cellulose). Furthermore, different PTM PeTUA1 isoforms located at different developmental stages during secondary cell wall deposition in Populus. Based on our previous data, we propose to characterize the biological function of PeTUA1 gene and its PTM during secondary cell wall biosynthesis in poplar. Genetic, biochemistry and molecular biology approaches will be employed as well as tension wood induction system and single-tissue RNA-seq technique. We finally will provide a PeTUA1-involved molecular regulation network during secondary cell wall biosynthesis. The outcoming evidences will offer potential strategies for genetical improvement of wood quality.