What was old is new again: thermal adaptation within clonal lineages during range expansion in a fungal pathogen

Range-expanding species are expected to gain an increasing importance in the context of global change. They provide a great opportunity to study contemporary evolutionary changes and to unravel the mechanisms of evolution. Cryphonectria parasitica, the causal agent of chestnut blight, originating from Asia, has been spread since the beginning of the 20th century into different continents. We took advantage of the C. parasitica recent emergence in northern France to study the changes in population genetic structure and in phenotypic traits along this colonization and climatic gradient. Four hundred twenty-seven C. parasitica isolates were sampled in 47 chestnut sites in northern France. The C. parasitica outbreak in the north was found to be due to the expansion of five dominant clonal groups from southern France and to the emergence of a few rare recombined genotypes. The evolutionary changes during C. parasitica range expansion were studied by analyzing phenotypic changes in isolates f...在全球变化的背景下，分布范围扩张物种的研究重要性与日俱增。这类物种为探究当代演化过程、解析演化机制提供了绝佳契机。栗疫病菌（Cryphonectria parasitica）是板栗疫病的病原菌，其原生分布区域为亚洲，自20世纪初起便已扩散至各大洲。本研究依托栗疫病菌在法国北部的新近定殖事件，沿着该物种的定殖扩散路径与气候梯度，分析其种群遗传结构与表型性状的变化。研究团队在法国北部的47个板栗样地中共采集到427株栗疫病菌分离株。研究发现，法国北部的栗疫病菌暴发，源于5个来自法国南部的优势克隆群的扩散，以及少量稀有重组基因型的出现。本研究通过分析分离株的表型特征变化，对栗疫病菌分布范围扩张过程中的演化改变展开了探究……