PDF(Pubmed)
Abstract：
Tree growth performance can be partly explained by genetics, while a large proportion of growth variation is thought to be controlled by environmental factors. However, to what extent DNA methylation, a stable epigenetic modification, contributes to phenotypic plasticity in the growth performance of long-lived trees remains unclear. In this study, a comparative analysis of targeted DNA genotyping, DNA methylation and mRNAseq profiling for needles of 44-year-old Douglas-fir trees (Pseudotsuga menziesii (Mirb.) Franco) having contrasting growth characteristics was performed. In total, we identified 195 differentially expressed genes (DEGs) and 115 differentially methylated loci (DML) that are associated with genes involved in fitness-related processes such as growth, stress management, plant development and energy resources. Interestingly, all four intronic DML were identified in mega-sized (between 100 and 180 kbp in length) and highly expressed genes, suggesting specialized regulation mechanisms of these long intron genes in gymnosperms. DNA repetitive sequences mainly comprising long-terminal repeats of retroelements are involved in growth-associated DNA methylation regulation (both hyper- and hypomethylation) of 99 DML (86.1% of total DML). Furthermore, nearly 14% of the DML was not tagged by single nucleotide polymorphisms, suggesting a unique contribution of the epigenetic variation in tree growth.
摘要：
树木的生长性能可以部分由遗传学解释，而很大一部分生长变化被认为是受环境因素控制的。然而,DNA甲基化到什么程度，稳定的表观遗传修饰，有助于长寿树木生长性能的表型可塑性尚不清楚。在这项研究中,靶向DNA基因分型的比较分析，44岁的道格拉斯冷杉树针头的DNA甲基化和mRNAseq分析（Pseudotsugamenziesii（Mirb。)Franco)具有相反的生长特性。总的来说,我们确定了195个差异表达基因（DEGs）和115个差异甲基化位点（DML），这些基因与健康相关过程（如生长）相关。压力管理，植物开发和能源资源。有趣的是,所有四个内含子DML都被鉴定为巨型（长度在100和180kbp之间）和高表达的基因，提示裸子植物中这些长内含子基因的专门调控机制。主要包含逆转录元件长末端重复序列的DNA重复序列参与99DML（占总DML的86.1％）的生长相关DNA甲基化调节（高甲基化和低甲基化）。此外，近14%的DML没有被单核苷酸多态性标记，表明表观遗传变异在树木生长中的独特贡献。
