Data from: Genetic signatures of variation in population size in a native fungal pathogen after the recent massive plantation of its host tree

Historical fluctuations in forests' distribution driven by past climate changes and anthropogenic activities can have large impacts on the demographic history of pathogens that have a long co-evolution history with these host trees. Using a population genetic approach, we investigated that hypothesis by reconstructing the demographic history of Armillaria ostoyae, one of the major pathogens of the maritime pine (Pinus pinaster), in the largest monospecific pine planted forest in Europe (south-western France). Genetic structure analyses and approximate Bayesian computation approaches revealed that a single pathogen population underwent a severe reduction in effective size (12 times lower) 1080-2080 generations ago, followed by an expansion (4 times higher) during the last 4 generations. These results are consistent with the history of the maritime pine forest in the region characterized by a strong recession during the last glaciation (~19 000 years ago) and massive plantations during the second half of the nineteenth century. Results suggest that recent and intensive plantations of a host tree population have offered the opportunity for a rapid spread and adaptation of their pathogens.由古气候变化与人类活动共同驱动的森林分布历史波动，可对与宿主树木长期协同进化的病原菌的种群历史动态产生显著影响。本研究借助种群遗传学研究手段，以欧洲规模最大的单一树种松类人工林——法国西南部的滨海松（Pinus pinaster）人工林为研究区域，针对其主要病原菌之一的硬蜜环菌（Armillaria ostoyae）的种群历史动态展开假说验证。遗传结构分析与近似贝叶斯计算（approximate Bayesian computation）结果显示，该病原菌的单一种群在1080至2080个世代前经历了剧烈的有效种群规模缩减（降幅达12倍），随后在近4个世代中实现了种群扩张（增幅达4倍）。上述结果与该区域滨海松林的历史演化轨迹高度吻合：末次冰期（约19000年前）该区域滨海松林曾经历严重衰退，而19世纪下半叶则开展了大规模人工造林活动。研究结果表明，宿主树木种群的近期高强度人工造林活动，为其病原菌的快速传播与适应性进化提供了有利条件。