毛果杨PtrMYB161基因在木质部发育中的表达调控

Regulation of PtrMYB161 Gene in Xylem Development in Populus trichocarpa

木材形成是一个复杂的发育过程包括维管形成层分化形成次生木质部以及木质部中细胞壁的加厚等,其中MYB家族转录因子在此过程中发挥着重要调控作用。通过RNA-seq对毛果杨(Populus trichocarpa)基因组中的MYB基因表达模式分析,结果发现PtrMYB161基因在木质部特异表达,并且主要在纤维细胞中特异表达。为解析该基因在木质部发育中的表达调控功能,构建35S::PtrMYB161植物表达载体并进行毛果杨遗传转化,共获得6个PtrMYB161过表达转基因株系。RT-PCR结果表明,在过表达转基因株系中PtrMYB161基因的表达丰度增加500~5 000倍。表型和组织形态学分析表明,表达丰度增加最多的L5株系表现出明显的植株矮小、叶片面积小、茎节短、茎直径小、木质部面积减小及纤维细胞数量降低等特征,表明PtrMYB161基因参与调控毛果杨木质部发育等过程并起着至关重要的作用。

Wood formation is a complex developmental process involving differentiation of secondary xylem cells from the vascular cambium,followed by thickening cell wall. MYB transcription factors play important roles in the regulation of this process.By RNA-seq analysis of MYB family genes in Populus trichocarpa genome,PtrM YB161 is expressed specifically in fiber cells of the xylem in P. trichocarpa. In order to further investigate its function in xylem development,we constructed plant overexpression vector（ 35 S：：PtrM YB161） and generated transgenic plants in P. trichocarpa. By quantitative real time PCR analysis,six transgenic lines were obtained with PtrM YB161 overexpression of 500-5 000 times compared with that of wildtype plants. By phenotypic and tissue morphology analysis,the highest-expressed Line 5 is dwarfed with smaller leaf,thinner stem,and less fiber cells,indicating that PtrM YB161 plays important roles in regulation of xylem development in Populus trichocarpa.