杨树维管形成层活动响应赤霉素的lncRNA挖掘与功能分析

Increases in tree girth are generated by the activities of the vascular cambium, which produces secondary xylem and phloem. In northern temperate regions, the vascular cambium of woody plants has a seasonal cycle of activity and dormancy. The initiation, duration, and cessation of vascular cambium activity are usually decisive factors in determining the quantity and quality of wood. In this research, a reliable experimental system was established in which the dormancy of poplar could be induced or released artificially. By the RNA sequencing technique, we analyze the differentially expressed lncRNA during the dormancy-activation transition of cambium. An interesting finding was that lncRNA, which involved in the GA signal pathway. Anatomy, molecular biology and plant physiology methods will be used together to investigate how lncRNA and its target genes involve to regulate cambium annual cycle transition though gibberellin signal. This research will reveal the molecular mechanism of cambial activity cycle regulation in various levels, which will also provide a the oretical basis for forest production, wood properties related tree breeding with high yield and quality.

木材是树木维管形成层活动的产物，维管形成层活动具有活动期-休眠期的周期性转换，这种年周期特性于树木适应环境及木材产量、品质形成具有重要意义。申请人在前期的研究工作中，建立人工诱导形成层活动周期转变的实验体系，通过高通量测序及生物信息学分析，鉴定了在毛白杨形成层活动周期各个阶段差异表达的lncRNA。然而，其具体作用的分子机制和上下游互作因子尚不清楚。本项目在前期研究基础上，综合细胞生物学、生物信息学、分子生物学、植物生理学等研究手段，探讨lncRNA及其互作因子，从中挖掘参与赤霉素信号通路特异性表达lncRNA(TCONS_00068047)及其靶基因GAI.2进行研究，并通过杨树遗传转化体系进行生物学功能验证。深入分析lncRNA及其靶基因如何通过赤霉素参与形成层活动周期调控，揭示维管形成层生理休眠的诱导、维持与解除，为林业生产、提高木材生长量、优质高产树种的定向选育提供重要科学依据。

木材是树木维管形成层活动的产物，维管形成层活动具有活动期-休眠期的周期性转换，这种年周期特性于树木适应环境及木材产量、品质形成具有重要意义。申请人通过高通量测序及生物信息学分析，鉴定了在毛白杨形成层活动周期各个阶段差异表达的非编码RNA，包括lncRNA、miRNA和circRNA。综合细胞生物学、生物信息学、分子生物学、植物生理学等研究手段，首先揭示了维管形成层年周期变化过程中多糖和细胞壁厚度有明显变化，并鉴定出2037和299个lncRNA在维管形成层期间有差异表达。此外，2037个新lncRNA中鉴定出1046个基因为靶基因，其中89个为miRNA前体或靶基因。进一步通过GO富集和KEGG途径分析lncRNA/circRNA-miRNA网络主要参与植物激素、细胞壁改变和叶绿素代谢的靶mRNA。最后通过杨树遗传转化体系进行miR396d及其靶基因TCP20、植物激素和光合作用相关lncRNA生物学功能验证。深入分析非编码及其靶基因如何通过赤霉素参与形成层活动周期调控，揭示维管形成层休眠的诱导、维持与解除。