Data from: Influences of environmental and spatial factors on genetic and epigenetic variations in Rhododendron oldhamii (Ericaceae)

Test of the relationship of genetic and particularly epigenetic variation with geographic isolation and environment is important to reveal potential environmental drivers for selection. Rhododendron oldhamii is widespread but inhabits fragmented subtropical forest landscapes and populations across its range may exhibit different levels of genetic and epigenetic structuring correlated to their environmental conditions. Here, we investigated the genetic and epigenetic variations and their ecological correlates in R. oldhamii. Genetic and epigenetic variations were surveyed using amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP), respectively. Using variation partitioning by redundant analysis (RDA), we examined the pure and spatially-structured environmental effects and pure spatial factors on genetic and epigenetic variations among individuals collected from 18 localities across R. oldhamii distribution range in Taiwan. We found that environments compared to geographic isolation among sites explained more genetic and epigenetic variations. Patchy distribution of the contemporary R. oldhamii populations was revealed by correlograms with patch size of approximately around 20-30 km based on the total genetic and epigenetic data. Spatial variables derived from the method of principal coordinates of neighbor matrices (PCNM), including PCNM3, PCNM5, PCNM7 and PCNM8 representing biotic processes, such as individual dispersal, were found to be important influencing potentially adaptive genetic and epigenetic variations. Annual mean temperature, annual precipitation, precipitation of the warmest quarter, aspect, slope and soil moisture were the most important environmental variables influencing potentially adaptive genetic and epigenetic variations, and could be particularly important for the evolution of local adaptation in R. oldhamii.

探究遗传变异，尤其是表观遗传变异与地理隔离及环境的关联，对于揭示潜在的选择环境驱动因子至关重要。奥尔德姆杜鹃（Rhododendron oldhamii）虽分布广泛，但栖息于碎片化的亚热带森林景观中，其分布区内的各类种群可能呈现与自身环境条件相关的不同程度的遗传与表观遗传结构。本研究以该物种为对象，对其遗传与表观遗传变异及其生态关联展开了系统调查。分别采用扩增片段长度多态性（amplified fragment length polymorphism, AFLP）与甲基化敏感扩增多态性（methylation-sensitive amplification polymorphism, MSAP）技术，对遗传变异与表观遗传变异进行了检测。本研究借助冗余分析（redundant analysis, RDA）开展变异分区分析，针对台湾地区奥尔德姆杜鹃分布范围内18个采样点的个体样本，解析了纯环境效应、空间结构化环境效应以及纯空间因子对遗传与表观遗传变异的影响。研究结果显示，相较于种群间的地理隔离，环境因子对遗传与表观遗传变异的解释贡献率更高。基于整体遗传与表观遗传数据构建的相关图分析表明，当代奥尔德姆杜鹃种群呈斑块状分布，斑块规模约为20~30 km。通过邻域矩阵主坐标分析（principal coordinates of neighbor matrices, PCNM）提取得到的空间变量（包括PCNM3、PCNM5、PCNM7与PCNM8）可表征个体扩散等生物过程，研究发现这些变量对潜在适应性遗传与表观遗传变异具有重要调控作用。年平均气温、年降水量、最热季降水量、坡向、坡度与土壤含水量，是影响潜在适应性遗传与表观遗传变异的核心环境变量，且可能对奥尔德姆杜鹃的本地适应进化具有关键意义。