Data from: 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. Heritability of growth rate under the three temperatures was substantial in all populations (0.58-0.76). Genetic variation was lower in populations with higher growth rate at the three temperatures and evolvability increased under heat stress in seven out of nine populations. Our findings imply that the distribution of this pathogen is unlikely to be genetically limited under climate warming, due to its high genetic variation and plasticity for thermal tolerance.

为预测植物病原菌对气候变暖的响应，需获取当前热适应、病原菌进化潜力及其二者间关联的相关数据。本研究以采自9个气候各异区域的大麦种群的真菌病原菌——大麦条斑病菌（Rhynchosporium commune）——的分离株为材料开展同质园试验。对126个遗传背景各异的分离株的克隆重复株，分别在12℃、18℃和22℃条件下测定其生长速率。与来自温度波动较小区域的种群相比，采自月温度波动幅度更大的气候区域的种群，在三种温度下的生长速率均更高。生长速率相关的群体分化系数（Q_ST）在22℃条件下显著高于中性微卫星位点的群体分化系数（G_ST），这与高温下生长的局部适应现象相符。在18℃条件下，我们发现生长速率存在稳定选择的证据，此时Q_ST显著低于G_ST。三种温度条件下的生长速率遗传力在所有种群中均较高，取值范围为0.58~0.76。在三种温度下生长速率更高的种群，其遗传变异水平更低；且9个种群中有7个在热胁迫下的可进化性有所提升。本研究结果表明，由于该病原菌在热耐受性方面具备较高的遗传变异与表型可塑性，气候变暖下其分布范围不太可能受到遗传因素的限制。