毛白杨PtoWOX1c参与形成层活性调控的机制研究

Wood formation is dependent on the activity of the vascular cambium. It has been confirmed that WUSCHEL - related homeobox (WOX) involved in regulating the stem cell division and differentiation in Arabidopsis. In previous study, PtoWOX family was identified in Populus tomentosa. Expression analysis in various tissues showed that PtoWOX1c exhibited a high expression level in cambium, while its homologous genes from herbaceous plant were expressed in leaf. Overexpression of PtoWOX1c can affect radial growth of stems, which indicated that PtoWOX1c involved in regulating the cambial activity, but its mechanism is unclear. In this project, we will analyze the expression patterns of PtoWOX1c in the cambium through GUS staining. The CRISPR/Cas9-generated ptowox1c mutant and PtoWOX1c overexpression plants will be used to analyze the function of PtoWOX1c. Combined with the CHIP-seq and protoplast transformation, we will identify the downstream target gene of PtoWOX1c, explore mechanism of PtoWOX1c in regulating cambial activity in poplar. Our study will provide theoretical guidance and technical approaches for the molecular genetic improvement of wood-property of forest trees.

木材的形成源于形成层分生组织的不断活动。在拟南芥等草本植物中的研究表明WUSCHEL-related homeobox（WOX）转录因子参与调控分生组织中干细胞的分裂和分化。前期通过对毛白杨WOX家族成员的鉴定及组织表达分析，发现PtoWOX1c在茎中形成层区域高丰度表达，不同于其同源基因在草本植物叶片中特异表达；超表达PtoWOX1c能够影响茎的径向生长，表明其参与调控形成层活性，但作用机制尚不清楚。基于之前的研究基础，本项目利用GUS染色分析PtoWOX1c在形成层活动中的精细表达模式；通过对PtoWOX1c基因编辑突变体和超表达转基因植株表型分析，解析PtoWOX1c的生物学功能；利用染色质免疫沉淀和原生质体转化等实验鉴定PtoWOX1c的下游靶基因，以揭示PtoWOX1c在形成层活性调控中的作用机制，为提高木材产量和品质的分子育种提供理论指导和技术途径。

木材的形成源于形成层分生组织的不断活动。WUSCHELrelated homeobox（WOX）转录因子参与调控分生组织中干细胞的分裂和分化。以WOX家族成员PtoWOX1c为研究对象，定量结果显示PtoWOX1c在茎中高丰度表达；亚细胞定位结果显示其定位在细胞核中；酵母实验证明其具有转录激活活性，其转录活性集中在PtoWOX1c蛋白的C端；超表达PtoWOX1c能够增强形成层向木质部的发育；通过酵母双杂交文库筛选，证明PtoWOX1c能够与WUSa、NAC102和MLP43互作；利用转录组、染色质免疫沉淀和酵母单杂交实验对下游基因进行分析，结果显示PtoWOX1c能够结合到LRP13启动子，正调控其表达。这一研究为提高木材产量和品质的分子育种提供理论指导和技术途径。