Data from: Host resistance and pathogen aggressiveness are key determinants of coinfection in the wild

Coinfection, whereby the same host is infected by more than one pathogen strain, may favor faster host exploitation rates as strains compete for the same limited resources. Hence, coinfection is expected to have major consequences for pathogen evolution, virulence and epidemiology. Theory predicts genetic variation in host resistance and pathogen infectivity to play a key role in how coinfections are formed. The limited number of studies available have demonstrated coinfection to be a common phenomenon, but little is known about how coinfection varies in space, and what its determinants are. Our aim is to understand how variation in host resistance and pathogen infectivity and aggressiveness contribute to how coinfections are formed in the interaction between fungal pathogen Podosphaera plantaginis and Plantago lanceolata. Our phenotyping study reveals that more aggressive strains are more likely to form coinfections than less aggressive strains in the natural populations. In the natural populations most of the variation in coinfection is found at the individual plant level, and results from a common garden study confirm the prevalence of coinfection to vary significantly among host genotypes. These results show that genetic variation in both the host and pathogen populations are key determinants of coinfection in the wild共侵染（Coinfection）指同一宿主被多种病原菌菌株侵染的现象，当菌株因争夺有限资源产生竞争时，可能会加快病原菌对宿主资源的利用速率。因此，共侵染被认为会对病原菌演化、毒力以及流行病学产生重要影响。理论预测，宿主抗性与病原菌侵染性的遗传变异，在共侵染的形成过程中发挥关键作用。现有相关研究数量有限，已有研究证实共侵染是一种普遍现象，但目前对共侵染的空间分布差异及其决定因素仍知之甚少。本研究旨在明确，在真菌病原菌车前白粉菌（Podosphaera plantaginis）与长叶车前（Plantago lanceolata）的互作体系中，宿主抗性、病原菌侵染性与致病力的变异如何影响共侵染的形成。本项表型鉴定研究显示，在自然种群中，致病力更强的菌株相较于弱致病力菌株，更易形成共侵染。在自然种群中，共侵染的绝大多数变异体现在单个植株水平；且同质园实验结果证实，共侵染的发生率在宿主基因型间存在显著差异。上述结果表明，宿主与病原菌种群的遗传变异，是野外环境中共侵染形成的核心决定因素。