Local adaptation and evolutionary potential along a temperature gradient in the fungal pathogen Rhynchosporium commune

To predict the response of plant pathogens to climate warming, data are needed on current thermal adaptation, the pathogen’s evolutionary potential and the link between them. We conducted a common garden experiment using isolates of the fungal pathogen Rhynchosporium commune from nine barley populations representing climatically diverse locations. Clonal replicates of 126 genetically distinct isolates were assessed for their growth rate at 12°C, 18°C and 22°C. Populations originating from climates with higher monthly temperature variation had higher growth rate at all three temperatures compared to populations from climates with less temperature fluctuation. Population differentiation in growth rate (Q_ST) was significantly higher at 22°C than population differentiation for neutral microsatellite loci (G_ST), consistent with local adaptation for growth at higher temperatures. At 18°C we found evidence for stabilizing selection for growth rate as Q_ST was significantly lower than G_ST. H...为预测植物病原菌对气候变暖的响应，需获取当前热适应情况、病原菌的进化潜力以及二者间的关联。我们开展了共同花园实验（common garden experiment），以覆盖气候多样区域的9个大麦种群来源的真菌病原菌禾谷喙孢霉（Rhynchosporium commune）分离株为实验材料。对126个遗传背景各异的分离株的克隆复制品（clonal replicates），分别在12℃、18℃与22℃三个温度下测定其生长速率。相较于来自温度波动较弱气候区域的种群，源自月度温度变幅更大气候区域的种群，在三个测试温度下的生长速率均显著更高。生长速率的种群分化（Q_ST）在22℃时显著高于中性微卫星位点（microsatellite loci）的种群分化（G_ST），这与高温环境下生长相关的局部适应现象相符。在18℃时，我们发现存在对生长速率的稳定选择，此时Q_ST显著低于G_ST。H...