Data from: Host resistance and pathogen infectivity in host populations with varying connectivity

Theory predicts that hosts and pathogens will evolve higher resistance and aggressiveness in systems where populations are spatially connected than in situations where populations are isolated and dispersal is more local. In a large cross-inoculation experiment we surveyed patterns of host resistance and pathogen infectivity in anther-smut diseased Viscaria alpina populations from three contrasting areas where populations range from continuous, through patchy but spatially connected to highly isolated demes. In agreement with theory, isolated populations of V. alpina were more susceptible on average than either patchily distributed or continuous populations. While increased dispersal in connected systems increases disease spread, it may also increase host gene flow and the potential for greater host resistance to evolve. In the Viscaria-Microbotryum system, pathogen infectivity mirrored patterns of host resistance with strains from the isolated populations being the least infective and strains from the more resistant continuous populations being the most infective on average, suggesting that high resistance selects for high infectivity. To our knowledge this study is the first to characterize the impacts of varying spatial connectivity on patterns of host resistance and pathogen infectivity in a natural system.

理论预测，相较于种群隔离且扩散更局限的系统，在空间连通的种群系统中，宿主与病原物会演化出更强的抗性与致病力。本研究开展了一项大型交叉接种实验（cross-inoculation），对来自三个差异显著区域的染花药黑粉病（anther-smut）高山剪秋罗（Viscaria alpina）种群的宿主抗性与病原物侵染性模式展开了调查；这些区域的种群分布模式涵盖连续分布、斑块状但空间连通，以及高度隔离的同类群（deme）。与理论预测一致，高山剪秋罗的隔离种群平均易感程度显著高于斑块状分布或连续分布的种群。尽管连通系统中扩散能力提升会促进病害传播，但同时也可能增强宿主的基因交流水平，进而为宿主演化出更强抗性提供潜在可能。在高山剪秋罗-微黑粉菌属（Microbotryum）共生系统中，病原物的侵染性与宿主抗性模式高度匹配：来自隔离种群的菌株平均侵染性最弱，而源自抗性更强的连续分布种群的菌株平均侵染性最强，这表明高抗性宿主会对高侵染性病原物产生定向选择。据我们所知，本研究首次在自然系统中阐明了空间连通性差异对宿主抗性与病原物侵染性模式的影响。